update apollo demo server address (#4628)

README.md

@@ -23,7 +23,7 @@ For more details of the product introduction, please refer [Introduction to Apol
 For local demo purpose, please refer [Quick Start](https://www.apolloconfig.com/#/zh/deployment/quick-start).
 
 Demo Environment:
-- [http://106.54.227.205](http://106.54.227.205/)
+- [http://81.68.181.139](http://81.68.181.139/)
 - User/Password: apollo/admin
 
 # Screenshots

docs/en/README.md

@@ -15,7 +15,7 @@ For more details of the product introduction, please refer [Introduction to Apol
 For local demo purpose, please refer [Quick Start](en/deployment/quick-start).
 
 Demo Environment:
-- [http://106.54.227.205](http://106.54.227.205/)
+- [http://81.68.181.139](http://81.68.181.139/)
 - User/Password: apollo/admin
 
 # Screenshots

docs/zh/README.md

@@ -16,7 +16,7 @@ Java客户端不依赖任何框架，能够运行于所有Java运行时环境，
 
 演示环境（Demo）:
 
-- [http://106.54.227.205](http://106.54.227.205/)
+- [http://81.68.181.139](http://81.68.181.139/)
 - 账号/密码:apollo/admin
 
 > 如访问GitHub速度缓慢，可以访问[Gitee镜像](https://gitee.com/apolloconfig/apollo)，不定期同步