Docker Images Build CI action: add updated version from release-20.0 back in prep for v21 release

[rohit-nayak-ps]

Description

The docker images build action was deleted temporarily in #16759. However we do need this action to build for release tags. Given that we have v21.0 coming up, this PR adds the workflow back. However it only runs it for the tags

  push:
    branches:
      - main
    tags:
      - 'v[2-9][0-9]*.*' # run only on tags greater or equal to v20.0.0 where this new way of building docker image was changed
  workflow_dispatch:

Note that this has also added the workflow_dispatch trigger, so that we can manually run this from the GitHub UI easily if required. We had an issue recently with Docker Hub throttling and it was non-trivial to find the failed action to rerun.

This also changes the github instance it runs on to ubuntu-latest in line with the recently announced instance changes in GitHub Actions.

Related Issue(s)

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

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