Update registry.

docker-compose.yml

@@ -12,7 +12,7 @@ services:
           --spider
           http://127.0.0.1:5000/v2/_catalog
           || exit 1
-    image: registry.hub.docker.com/library/registry:2.7.1
+    image: registry.hub.docker.com/library/registry:2.8.1
     restart: always
     volumes:
       - "registry:/var/lib/registry"