ci: GitHub Actions workflow to publish Docker image on release

Triggered on release published, builds and pushes to
droideparanoico/dostalgia on Docker Hub with tags:
  - :latest (on default branch releases)
  - :<version> (e.g. :1.2.3)
  - :<major>.<minor> (e.g. :1.2)

.github/workflows/docker-publish.yml

@@ -0,0 +1,45 @@
+name: Publish Docker image
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_HUB_USERNAME }}
+          password: ${{ secrets.DOCKER_HUB_TOKEN }}
+
+      - name: Extract tags
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: droideparanoico/dostalgia
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}