New boolean input tag_with_latest

New boolean input tag_with_latest

It would add the ability for users to better set when to push as latest, such as evaluating an expression for example.

Example: tag as latest when push git tags

- uses: docker/build-push-action@v1
  with:
    username: ${{ secrets.DOCKER_USERNAME }}
    password: ${{ secrets.DOCKER_PASSWORD }}
    repository: felipecassiors/argbash-test
    add_git_labels: true
    # Only push as latest when push a git tag
    tag_with_latest: ${{ startsWith(github.ref, 'refs/tags/') }}
    tag_with_ref: true
    tag_with_sha: true

Usage with tag_with_ref

If tag_with_latest property is defined alongside tag_with_ref, then the strategy of push as latest when the branch is master from tag_with_ref should be ignored.

[ibnesayeed]

I usually publish bleeding-edge changes of the master branch with master tag and reserve the latest for when the repo is tagged. This way, people who pull my images without explicit tags can always get something that I explicitly released.

• on push to a branch
  • build image with the branch name as the image tag
• on release/repo tag
  • build image with the tag ref as the image tag
  • build image with latest tag

[crazy-max]

Solved by #119. See https://github.com/docker/build-push-action#complete-workflow