disable worker arm/v7 support for now

.github/workflows/call-docker-build-worker.yaml

@@ -76,7 +76,9 @@ jobs:
       
       ### platforms to build for, defaults to linux/amd64
       ### other options: linux/amd64,linux/arm64,linux/arm/v7
-      platforms: linux/amd64,linux/arm64,linux/arm/v7
+      # FIXME worker arm/v7 support doesn't build in .net core 3.1 with QEMU
+      # a fix would likely run the .net build on amd64 but with a target of arm/v7
+      platforms: linux/amd64,linux/arm64
       
       ### Create a PR comment with image tags and labels
       ### defaults to false