multi-platform build, build on tag

.github/workflows/build.yml

@@ -3,6 +3,8 @@ name: Build on push
 on:
   push:
     branches: [ "*" ]
+    tags:
+      - 'v*'
   pull_request:
     branches: [ "main" ]
   workflow_dispatch: {}
@@ -17,8 +19,13 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
       - name: Set up Docker Buildx
+        id: buildx
         uses: docker/setup-buildx-action@v1
+      - name: Available platforms
+        run: echo ${{ steps.buildx.outputs.platforms }}
       - name: Log in to the Container registry
         uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
         with:
@@ -35,6 +42,7 @@ jobs:
         uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
         with:
           context: .
+          platforms: linux/amd64, linux/arm64
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}