github_package_repository.yml

name: Publish Docker image to GitHub Package Registry
on: 
  push:
    branches: master
jobs:
  build:
    runs-on: ubuntu-latest 
    steps:

    - name: Checkout Master
      uses: actions/checkout@master

     #This Action Emits 2 Variables, IMAGE_SHA_NAME and IMAGE_URL 
     #which you can reference in subsequent steps
    - name: Publish Docker Image to GPR
      uses: machine-learning-apps/gpr-docker-publish@master
      id: docker
      with:
        IMAGE_NAME: 'uptimerobot-dark-mode'
        TAG: 'latest'
        DOCKERFILE_PATH: 'Dockerfile'
        BUILD_CONTEXT: '.'
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

    # This second step is illustrative and shows how to reference the 
    # output variables.  This is completely optional.
    - name: Show outputs of previous step
      run: |
        echo "The name:tag of the Docker Image is: $VAR1"
        echo "The docker image is hosted at $VAR2"
      env:
        VAR1: ${{ steps.docker.outputs.IMAGE_SHA_NAME }}
        VAR2: ${{ steps.docker.outputs.IMAGE_URL }}