TUN-6652: Publish dockerfile for both amd64 and arm64

This change seeks to push an arm64 built image to dockerhub for arm users to run. This should spin cloudflared on arm machines without the warning
WARNING: The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8) and no specific platform was requested

.docker-images

@@ -1,6 +1,6 @@
 images:
   - name: cloudflared
-    dockerfile: Dockerfile
+    dockerfile: Dockerfile.$ARCH
     context: .
     versions: 
       - latest
@@ -8,3 +8,6 @@ images:
     - name: docker.io/cloudflare
       user: env:DOCKER_USER
       password: env:DOCKER_PASSWORD
+    architectures:
+    - amd64
+    - arm64