Add new GH workflow to publish images

With each published release.

Signed-off-by: Josh Berkus <[email protected]>

.github/workflows/release-image.yml

@@ -0,0 +1,36 @@
+name: Image On Release
+
+name: Publish Docker image
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  push_to_registry:
+    name: Push Docker image to GHCR
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v3
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}