ci: create build-docker.yml

.github/workflows/build-docker.yml

@@ -0,0 +1,33 @@
+name: Build Docker Image
+
+on:
+  push:
+    branches: [ "main" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Setup Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
+    - name: Login to GitHub Container Registry
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Build Images
+      uses: docker/build-push-action@v6
+      env:
+        DOCKER_BUILD_SUMMARY: false
+      with:
+        context: .
+        file: Dockerfile
+        platforms: linux/amd64,linux/arm64
+        push: true
+        tags: ghcr.io/ietf-tools/upgrade-page:latest