action to detect a keyword in the commit summary line

[keewis]

follow-up to #4729 and #4730

To use the detect-ci-trigger action in workflows, add a new job:

  detect-ci-trigger:
    name: Detect CI Trigger
    runs-on: ubuntu-latest
    outputs:
      triggered: ${{ steps.detect-trigger.outputs.trigger-found }}
    steps:
    - uses: actions/checkout@v2
    - uses: ./.github/actions/detect-ci-trigger
      id: detect-trigger
      with:
        keyword: "<keyword>"

then require the new job in jobs that should be conditionally skipped:

  my-ci-job:
    runs-on: ubuntu-latest
    needs: detect-ci-trigger
    if: needs.detect-ci-trigger.outputs.triggered == 'false'  # for skip-ci
    # if: needs.detect-ci-trigger.outputs.triggered == 'true'  # for test-upstream
    steps:
    - actions/checkout@v2
    # ...

unfortunately, this still requires actions/checkout with fetch-depth, I can't seem to get a git fetch in the action script to work. Edit: git fetch --deepen=1 instead of git fetch --depth=2 seems to work.

cc @andersy005

[keewis]

should we merge this first and then use it in #4729 and #4730?

[andersy005]

This looks great 👍🏽

should we merge this first and then use it in #4729 and #4730?

Sounds good

[keewis]

thanks for the review, @andersy005.