Update Operator build image to Alpine 3.20

What does this MR do and why?

Use Alpine 3.20 for the base image of Operator build image.

There is a significant gap in Podman version between Alpine 3.19 and 3.20.

This upgrade may fix the issue with the pipeline failure in gitlab-org/cloud-native/gitlab-operator#1687 (closed).

As a result of this change, in addition to core utilities (curl, git, etc), the following packages are upgraded:

• Podman: 4.8.3-r3 to 5.0.3-r3
• Buildah: 1.33.6-r3 to 1.35.4-r0

Checklist

• (If applicable) Add patches if required for upgrading Ruby version in https://gitlab.com/gitlab-org/gitlab-build-images/-/tree/master/patches/ruby.