Bump alpine from 3.20 to 3.21 (#4962)

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

@@ -1,7 +1,7 @@
 # Copyright (c) Mondoo, Inc.
 # SPDX-License-Identifier: BUSL-1.1
 
-FROM alpine:3.20 AS root
+FROM alpine:3.21 AS root
 RUN apk update &&\
     apk add ca-certificates wget tar &&\
     rm -rf /var/cache/apk/*