Bump alpine from 3.20 to 3.21 (#122)

Bumps alpine from 3.20 to 3.21.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Dockerfile

@@ -26,7 +26,7 @@ RUN --mount=type=cache,id=go-build-${TARGETOS}-${TARGETARCH}${TARGETVARIANT},tar
 			./cmd/${PKG_NAME}
 RUN mv bin/${PKG_NAME}* /bin/
 
-FROM alpine:3.20 AS runtime
+FROM alpine:3.21 AS runtime
 
 ARG PKG_NAME
 ARG VCS_REF