Simplify CI to mdpress only

09_network/9.7_advanced_networking.md

@@ -91,7 +91,6 @@ docker network create --driver overlay \
   my-custom-overlay
 
 # 在 Compose 中使用 overlay 网络
-version: '3.9'
 services:
   web:
     image: nginx
@@ -284,8 +283,6 @@ docker exec <container_id> cat /etc/resolv.conf
 **Docker Compose DNS 配置：**
 
 ```yaml
-version: '3.9'
-
 services:
   web:
     image: nginx
@@ -343,8 +340,6 @@ docker run -it --network mynet busybox sh
 **Compose 服务名自动发现：**
 
 ```yaml
-version: '3.9'
-
 services:
   frontend:
     image: nginx