I successfully pushed my image to Github Container Registry with the following workflow

name: GHCR-DigitalOcean

on:
  # Trigger the workflow on push
  push:
    branches:
      - main

jobs:
  push_to_registry:
    name: Push to GHCR -> DigitlOcean
    runs-on: ubuntu-latest

    steps:
      # Checkout the Repository
      - name: Checking out the repository
        uses: actions/checkout@v2

      # Setting up Docker Builder
      - name: Set up Docker Builder
        uses: docker/setup-buildx-action@v1

      # Set Github Access Token with "write:packages" scope for Github Container Registry.
      # Then go to repository setings and add the copied token as a secret called "CR_PAT"
      # https://github.com/settings/tokens/new?scopes=repo,write:packages&description=Github+Container+Registry
      - name: Log into GitHub Container Registry
        uses: docker/login-action@v1
        with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ secrets.CR_PAT }}

      # Push to Github Container Registry
      - name: Push to Github Container Registry
        uses: docker/build-push-action@v2
        with:
          context: .
          version: latest
          file: dockerfile
          push: true
          tags: ghcr.io/${{ github.repository }}:latest

Unfortunately I got stuck by the ssh handshake as I try to provide the credentials instead of a key.

2020/12/*** 13:30:13 ssh: handshake failed: ssh: unable to authenticate, attempted methods [none password], no supported methods remain

  deploy_to_digital_ocean_dropplet:
    name: Deploy to Digital Ocean Droplet
    runs-on: ubuntu-latest
    needs: push_to_github_container_registry

    steps:
      - name: Deploy to Digital Ocean droplet via SSH action
        uses: appleboy/ssh-action@v0.1.3
        with:
          HOST: ${{ secrets.HOST }}
          USERNAME: ${{ secrets.USERNAME }}
          PASSWORD: ${{ secrets.PASSWORD }}
          PORT: ${{ secrets.PORT }}
          script: |
            # Stop running container
            docker stop ${{ github.repository_owner }}

            # Remove old container
            docker rm ${{ github.repository_owner }}

            # Login to Github Container Registry
            docker login https://ghcr.io -u ${{ github.repository_owner }} -p ${{ secrets.CR_PAT }}

            # Pull the Docker Image 
            docker pull ghcr.io/${{ github.repository }}:latest

            # Run a new container from a new image
            docker run -d \
            --restart always \
            --env-file .env \
            -p 8000:8080 \
            --name $(echo $${{ github.repository }})