Remove additional -U of apk in Dockerfile

[PeterDaveHello]

There's no need to use -U with --no-cache together here ;)

[Mzack9999]

lgtm - nice catch!

> docker build .
[+] Building 77.0s (16/16) FINISHED
 => [internal] load .dockerignore                                                                                                                                                                                                                                                                                           0.1s
 => => transferring context: 2B                                                                                                                                                                                                                                                                                             0.0s 
 => [internal] load build definition from Dockerfile                                                                                                                                                                                                                                                                        0.1s 
 => => transferring dockerfile: 407B                                                                                                                                                                                                                                                                                        0.0s 
 => [internal] load metadata for docker.io/library/golang:1.20.4-alpine                                                                                                                                                                                                                                                     2.2s
 => [internal] load metadata for docker.io/library/alpine:3.18.0                                                                                                                                                                                                                                                            2.1s 
 => [stage-1 1/3] FROM docker.io/library/alpine:3.18.0@sha256:02bb6f428431fbc2809c5d1b41eab5a68350194fb508869a33cb1af4444c9b11                                                                                                                                                                                              1.1s
 => => resolve docker.io/library/alpine:3.18.0@sha256:02bb6f428431fbc2809c5d1b41eab5a68350194fb508869a33cb1af4444c9b11                                                                                                                                                                                                      0.1s 
 => => sha256:02bb6f428431fbc2809c5d1b41eab5a68350194fb508869a33cb1af4444c9b11 1.64kB / 1.64kB                                                                                                                                                                                                                              0.0s 
 => => sha256:c0669ef34cdc14332c0f1ab0c2c01acb91d96014b172f1a76f3a39e63d1f0bda 528B / 528B                                                                                                                                                                                                                                  0.0s 
 => => sha256:5e2b554c1c45d22c9d1aa836828828e320a26011b76c08631ac896cbc3625e3e 1.47kB / 1.47kB                                                                                                                                                                                                                              0.0s 
 => => sha256:8a49fdb3b6a5ff2bd8ec6a86c05b2922a0f7454579ecc07637e94dfd1d0639b6 3.40MB / 3.40MB                                                                                                                                                                                                                              0.8s
 => => extracting sha256:8a49fdb3b6a5ff2bd8ec6a86c05b2922a0f7454579ecc07637e94dfd1d0639b6                                                                                                                                                                                                                                   0.1s 
 => [build-env 1/7] FROM docker.io/library/golang:1.20.4-alpine@sha256:ee2f23f1a612da71b8a4cd78fec827f1e67b0a8546a98d257cca441a4ddbebcb                                                                                                                                                                                    18.4s 
 => => resolve docker.io/library/golang:1.20.4-alpine@sha256:ee2f23f1a612da71b8a4cd78fec827f1e67b0a8546a98d257cca441a4ddbebcb                                                                                                                                                                                               0.1s 
 => => sha256:ee2f23f1a612da71b8a4cd78fec827f1e67b0a8546a98d257cca441a4ddbebcb 1.65kB / 1.65kB                                                                                                                                                                                                                              0.0s 
 => => sha256:0a03b591c358a0bb02e39b93c30e955358dadd18dc507087a3b7f3912c17fe13 1.16kB / 1.16kB                                                                                                                                                                                                                              0.0s 
 => => sha256:98045bb148f1a5be15cdccc3c15f9c377a5eef737fc3cb901b910709c281ed9b 5.11kB / 5.11kB                                                                                                                                                                                                                              0.0s 
 => => sha256:8a49fdb3b6a5ff2bd8ec6a86c05b2922a0f7454579ecc07637e94dfd1d0639b6 3.40MB / 3.40MB                                                                                                                                                                                                                              0.8s 
 => => sha256:58116d8bf56953e5f30b7f50257c5bb2b5ba4aba460cb69f2ac57eea00aaa5dc 284.69kB / 284.69kB                                                                                                                                                                                                                          0.2s 
 => => sha256:00664777e466f6e514b4234fa4469f2ab6a5ff56e1a61dbec52b1308993bcb89 100.88MB / 100.88MB                                                                                                                                                                                                                         12.8s 
 => => sha256:2f4ab7ae68c01966b86cdd51607b26641445bc9985874e0a312410f687256b25 157B / 157B                                                                                                                                                                                                                                  0.6s
 => => extracting sha256:8a49fdb3b6a5ff2bd8ec6a86c05b2922a0f7454579ecc07637e94dfd1d0639b6                                                                                                                                                                                                                                  73.9s 
 => => extracting sha256:58116d8bf56953e5f30b7f50257c5bb2b5ba4aba460cb69f2ac57eea00aaa5dc                                                                                                                                                                                                                                   0.0s 
 => => extracting sha256:00664777e466f6e514b4234fa4469f2ab6a5ff56e1a61dbec52b1308993bcb89                                                                                                                                                                                                                                   4.9s 
 => => extracting sha256:2f4ab7ae68c01966b86cdd51607b26641445bc9985874e0a312410f687256b25                                                                                                                                                                                                                                   0.0s 
 => [internal] load build context                                                                                                                                                                                                                                                                                           0.8s 
 => => transferring context: 23.23MB                                                                                                                                                                                                                                                                                        0.7s 
 => [stage-1 2/3] RUN apk upgrade --no-cache     && apk add --no-cache bind-tools ca-certificates                                                                                                                                                                                                                           5.6s 
 => [build-env 2/7] RUN apk add build-base                                                                                                                                                                                                                                                                                 18.0s 
 => [build-env 3/7] WORKDIR /app                                                                                                                                                                                                                                                                                            0.1s 
 => [build-env 4/7] COPY . /app                                                                                                                                                                                                                                                                                             1.1s 
 => [build-env 5/7] WORKDIR /app/v2                                                                                                                                                                                                                                                                                         0.0s 
 => [build-env 6/7] RUN go mod download                                                                                                                                                                                                                                                                                    19.3s 
 => [build-env 7/7] RUN go build ./cmd/subfinder                                                                                                                                                                                                                                                                           16.7s 
 => [stage-1 3/3] COPY --from=build-env /app/v2/subfinder /usr/local/bin/                                                                                                                                                                                                                                                   0.8s 
 => exporting to image                                                                                                                                                                                                                                                                                                      0.2s 
 => => exporting layers                                                                                                                                                                                                                                                                                                     0.2s 
 => => writing image sha256:fbae5a8a96d5caaa37ac1b8ea886f11326f70304c839e88c76987910dd653850