Create Docker Github Package workflow

This commit creates a new workflow that builds a docker image and publishes it to Github Packages.

.github/workflows/publish-github-package.yml

@@ -0,0 +1,59 @@
+name: Docker Github Package
+
+on:
+  release:
+    types: [published]
+
+env:
+  IMAGE_NAME: cnwan-operator
+
+jobs:
+  # Run tests.
+  # See also https://docs.docker.com/docker-hub/builds/automated-testing/
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Run tests
+        run: |
+          if [ -f docker-compose.test.yml ]; then
+            docker-compose --file docker-compose.test.yml build
+            docker-compose --file docker-compose.test.yml run sut
+          else
+            docker build . --file Dockerfile
+          fi
+
+  # Push image to GitHub Packages.
+  # See also https://docs.docker.com/docker-hub/builds/
+  push:
+    # Ensure test job passes before pushing image.
+    needs: test
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Build image
+        run: docker build . --file Dockerfile --tag $IMAGE_NAME
+
+      - name: Log into registry
+        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login docker.pkg.github.com -u ${{ github.actor }} --password-stdin
+
+      - name: Push image
+        run: |
+          IMAGE_ID=docker.pkg.github.com/${{ github.repository }}/$IMAGE_NAME
+
+          # Change all uppercase to lowercase
+          IMAGE_ID=$(echo $IMAGE_ID | tr '[A-Z]' '[a-z]')
+
+          # Strip git ref prefix from version
+          VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')
+
+          echo IMAGE_ID=$IMAGE_ID
+          echo VERSION=$VERSION
+
+          docker tag $IMAGE_NAME $IMAGE_ID:$VERSION
+          docker push $IMAGE_ID:$VERSION