enable arm build

Author: toelke

.github/workflows/image-build.yml

@@ -18,6 +18,7 @@ jobs:
           push: false
           tags: ghcr.io/${{ github.repository }}:latest-amd64
           file: Dockerfile
+          platforms: linux/amd64,linux/arm64
 
   build-origin:
     name: Image build/origin

.github/workflows/image-push-master.yml

@@ -29,9 +29,10 @@ jobs:
           context: .
           push: true
           tags: |
-            ghcr.io/${{ github.repository }}:latest-amd64
-            ghcr.io/${{ github.repository }}:snapshot-amd64
+            ghcr.io/${{ github.repository }}:latest
+            ghcr.io/${{ github.repository }}:snapshot
           file: Dockerfile
+          platforms: linux/amd64,linux/arm64
 
   push-origin:
     name: Image push/origin