chore(deps): update docker.io/library/alpine docker tag to v3.18.8

Signed-off-by: cilium-renovate[bot] <134692979+cilium-renovate[bot]@users.noreply.github.com>

Dockerfile

@@ -76,7 +76,7 @@ RUN curl -L https://github.com/libbpf/bpftool/releases/download/${BPFTOOL_TAG}/b
 
 # Almost final step runs on target platform (might need emulation) and
 # retrieves (cross-)compiled binaries from builders
-FROM docker.io/library/alpine:3.18.3@sha256:7144f7bab3d4c2648d7e59409f15ec52a18006a128c733fcff20d3a4a54ba44a as base-build
+FROM docker.io/library/alpine:3.18.8@sha256:5292533eb4efd4b5cf35e93b5a2b7d0e07ea193224c49446c7802c19ee4f2da5 as base-build
 RUN apk add iproute2
 RUN mkdir /var/lib/tetragon/ && \
     mkdir -p /etc/tetragon/tetragon.conf.d/ && \

Dockerfile.operator

@@ -5,7 +5,7 @@
 
 ARG BASE_IMAGE=scratch
 ARG GOLANG_IMAGE=docker.io/library/golang:1.21.1@sha256:19600fdcae402165dcdab18cb9649540bde6be7274dedb5d205b2f84029fe909
-ARG ALPINE_IMAGE=docker.io/library/alpine:3.18.3@sha256:7144f7bab3d4c2648d7e59409f15ec52a18006a128c733fcff20d3a4a54ba44a
+ARG ALPINE_IMAGE=docker.io/library/alpine:3.18.8@sha256:5292533eb4efd4b5cf35e93b5a2b7d0e07ea193224c49446c7802c19ee4f2da5
 
 # BUILDPLATFORM is an automatic platform ARG enabled by Docker BuildKit.
 # Represents the plataform where the build is happening, do not mix with