Add a GitHub action for the release (#4)

.github/workflows/release.yaml

@@ -0,0 +1,33 @@
+name: release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v4
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d #v3.0.0
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@e6428a5c4e294a61438ed7f43155db912025b6b3 #v5.2.0
+        with:
+          images: knanao/runtasks-pr-comment
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@4a13e500e55cf31b7a5d59a38ab2040ab0f42f56 #v5.1.0
+        with:
+          context: .
+          file: ./Dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}