Add GitHub action to publish Docker image

.github/workflows/publish.yaml

@@ -0,0 +1,50 @@
+name: Publish Docker image
+
+on: push
+
+jobs:
+  publish-images:
+    name: Publish Docker Images
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      attestations: write
+    steps:
+      -
+        name: Check out repo
+        uses: actions/checkout@v4
+
+      -
+        name: Extract metadata for Docker
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ghcr.io/${{ github.repository }}
+
+      -
+        name: Login to GitHub Packages
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      -
+        name: Build and push Docker image
+        id: push
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          file: ./Dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+
+      -
+        name: Generate artifact attestation
+        uses: actions/attest-build-provenance@v1
+        with:
+          subject-name: ghcr.io/${{ github.repository }}
+          subject-digest: ${{ steps.push.outputs.digest }}
+          push-to-registry: true

Dockerfile

@@ -17,6 +17,10 @@ RUN set -eux; \
 
 FROM alpine:3.19
 
+LABEL org.opencontainers.image.source=https://github.com/codedmonkey/conductor
+LABEL org.opencontainers.image.description="Conductor PHP Package Registry"
+LABEL org.opencontainers.image.licenses=MIT
+
 ARG UID=1000
 ARG GID=1000