Fix wrong link

appendix/resources.md

@@ -15,7 +15,7 @@
 ## 实践参考
 
 * Dockerfile 参考：https://docs.docker.com/engine/reference/builder/
-* Dockerfile 最佳实践：https://docs.docker.com/engine/userguide/eng-image/dockerfile_best-practices/
+* Dockerfile 最佳实践：https://docs.docker.com/build/building/best-practices/
 
 ## 技术交流
 

repository/demo/docker-compose.yml

@@ -2,7 +2,7 @@
 
 services:
   registry:
-    image: registry
+    image: registry:2
     ports:
       - "443:5000"
     volumes: