Remove linux/arm/v6 and linux/arm/v7 build platforms (#17)

Author: wborn

.github/workflows/proxy.yml

@@ -26,7 +26,7 @@ jobs:
   image_proxy:
 
     env:
-      PLATFORM: linux/amd64,linux/aarch64,linux/arm/v7,linux/arm/v6
+      PLATFORM: linux/amd64,linux/aarch64
 
     runs-on: ubuntu-latest