Added dockerfile and github action to build and publish it

.github/workflows/release-docker.yml

@@ -0,0 +1,30 @@
+# .github/workflows/release-docker.yml
+name: Publish Docker image
+on:
+  push:
+    tags: ["v*.*.*"]        # every semantic-version tag
+permissions:
+  contents: read
+  packages: write
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: docker/Dockerfile
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: |
+            ghcr.io/mongodb/kingfisher:latest
+            ghcr.io/mongodb/kingfisher:${{ github.ref_name }}