fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE314-BUSYBOX-1920755
- https://snyk.io/vuln/SNYK-ALPINE314-OPENSSL-3314646
- https://snyk.io/vuln/SNYK-ALPINE314-OPENSSL-3314653
- https://snyk.io/vuln/SNYK-ALPINE314-OPENSSL-3368739
- https://snyk.io/vuln/SNYK-ALPINE314-ZLIB-2976174

Dockerfile

@@ -35,7 +35,7 @@ RUN go mod verify
 RUN go run build.go build
 
 # Final stage
-FROM alpine:3.14.2
+FROM alpine:3.16.7
 
 LABEL maintainer="Grafana team <hello@grafana.com>"