Publish multi-arch image with Docker buildx

.github/workflows/build.yml

@@ -0,0 +1,20 @@
+name: build
+
+on:
+  push:
+    branches: '*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: crazy-max/ghaction-docker-buildx@v1
+      - name: build
+        run: |
+          echo "${{ secrets.DOCKER_PASSWORD }}" | docker login --username "${{ secrets.DOCKER_USERNAME }}" --password-stdin
+          docker buildx build --platform "linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64" \
+            --output "type=image,push=true" \
+            --build-arg "REVISION=${GITHUB_SHA::8}" \
+            --tag "docker.io/stefanprodan/podinfo:multiarch" \
+            --file Dockerfile .