Adds action to build and push

.github/workflows/build-push.yml

@@ -0,0 +1,76 @@
+name: build-push
+run-name: 'build-push: versioned? ${{ github.event.inputs.versioned }} - latest? ${{ github.event.inputs.latest }}'
+
+on:
+  workflow_dispatch:
+    inputs:
+      versioned:
+        description: 'Push with versioned tag?'
+        required: true
+        type: boolean
+        default: true
+      latest:
+        description: 'Push with "latest" tag?'
+        required: true
+        type: boolean
+        default: true
+
+jobs:
+  build-test-push:
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Build
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          load: true
+          tags: sandpaper:testing
+
+      # - name: Test
+      #   run: |
+      #     expected=""
+      #     actual=""
+      #     if [ "$expected" = "$actual" ]; then
+      #       echo "Passed -   $actual"
+      #     else
+      #       echo "ERROR - Expected: $expected"
+      #       echo "          Actual: $actual"
+      #       status=1
+      #     fi
+
+      #     exit $status
+
+      - name: Create tag from sandpaper, varnish and pandoc versions
+        id: tag
+        run: |
+          sandpaper=$(grep "ARG sandpaper_version=" Dockerfile | cut -f2 -d"=")
+          varnish=$(grep "ARG varnish_version=" Dockerfile | cut -f2 -d"=")
+          pandoc=$(grep "ARG pandoc_version=" Dockerfile | cut -f2 -d"=")
+          echo "versions=s${sandpaper}-v${varnish}-p${pandoc}" >> $GITHUB_OUTPUT
+          echo $versions
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Push versioned
+        if: github.event.inputs.versioned == 'true'
+        run: |
+          docker image tag sandpaper:testing ghcr.io/uomresearchit/sandpaper:${{ steps.tag.outputs.versions }}
+          docker push ghcr.io/uomresearchit/sandpaper:${{ steps.tag.outputs.versions }}
+
+      - name: Push latest
+        if: github.event.inputs.latest == 'true'
+        run: |
+          docker image tag sandpaper:testing ghcr.io/uomresearchit/sandpaper:latest
+          docker push ghcr.io/uomresearchit/sandpaper::latest