Git metadata docker action

Allows you to define env variables needed for build/deploy in order to harmonize with the following gitlab variables:

• CI_COMMIT_BRANCH
• CI_COMMIT_REF_NAME
• CI_COMMIT_REF_SLUG
• CI_COMMIT_SHA
• CI_COMMIT_TAG

See : https://docs.gitlab.com/ee/ci/variables/predefined_variables.html

Example usage

    - name: Git metadata
      uses: allocine/action-git-metadata@master
      env:
        GITHUB_COMMIT_PR_SHA: ${{ github.event.pull_request.head.sha }}