build for both amd64 and arm64

Author: juruen

.github/workflows/docker-publish.yml

@@ -76,11 +76,12 @@ jobs:
         uses: docker/build-push-action@0565240e2d4ab88bba5387d719585280857ece09 # v5.0.0
         with:
           context: .
-          push: ${{ github.event_name != 'pull_request' }}
+          push: ${{ github.event_name != 'null' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
+          platforms: linux/amd64,linux/arm64
 
       # Sign the resulting Docker image digest except on PRs.
       # This will only write to the public Rekor transparency log when the Docker