build(deps): bump alpine from 3.20.3 to 3.21.2 (#571)

Bumps alpine from 3.20.3 to 3.21.2.

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

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

Author: dependabot[bot]

Dockerfile

@@ -12,6 +12,6 @@ COPY internal/ internal
 
 RUN go build -o /konstraint -ldflags="-X 'github.com/plexsystems/konstraint/internal/commands.version=${KONSTRAINT_VER}'"
 
-FROM alpine:3.20.3
+FROM alpine:3.21.2
 COPY --from=build /konstraint /usr/bin/konstraint
 ENTRYPOINT ["konstraint"]