Add Docker build automation

Author: jkmassel

.github/workflows/publish-docker-image.yml

@@ -0,0 +1,31 @@
+name: Publish Docker Image
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Login to Docker Hub
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v3
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
+    - name: Build and push
+      uses: docker/build-push-action@v6
+      with:
+        context: "{{defaultContext}}:wp_rs_web"
+        push: true
+        tags: automattic/wordpress-rs-web:latest