Provide staging container

[kachick]

• Add step guard for the trigger and actor
• Do not add latest tag # both is okay for timestamp tag
• Add pr-NUM tag
• Add comment by bot that includes published and you can test with this command ...
• Delete the package after merge
  • maybe needless since Add package cleanup action #467
  • It may be complex https://github.com/actions/delete-package-versions/blob/68fef8e117918624b377e5c3d0fa2bbe3f2b3b30/README.md?plain=1#L344-L373 - Feature request: Delete specific package version actions/delete-package-versions#34
  • Manually https://docs.github.com/en/packages/learn-github-packages/deleting-and-restoring-a-package
  • Manually https://github.com/orgs/community/discussions/24963#discussioncomment-3245987
    => GH_TOKEN=***** gh api -H "Accept: application/vnd.github+json" -H "X-GitHub-Api-Version: 2022-11-28" /users/kachick/packages/container/home/versions and can filter with jq '.[] | select(.name == "sha256:7a43c041ddef1c40f2c6fa1374787ebe5cb2780a97676087c5c25da267157405")'