Example workflow used in this article: https://medium.com/@merlin.pav/cc1e2aacd9da?source=friends_link&sk=dcb39201c9d8bf917e1329af08ea1719

github_article_sample_ci_workflow__publish.yaml

   - name: Login to gcloud registry
      id: gcloud
      uses: elgohr/gcloud-login-action@0.2
      with:
        account_key: ${{ secrets.GCLOUD_KEY }}
        
    - name: Publish Docker Image
      uses: elgohr/Publish-Docker-Github-Action@2.14
      env:
        SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
      with:
        name: ${{ env.DOCKER_IMAGE }}
        username: ${{ steps.gcloud.outputs.username }}
        password: ${{ steps.gcloud.outputs.password }}
        registry: ${{ env.DOCKER_REGISTRY }}
        buildargs: SSH_PRIVATE_KEY