Update 03-package.md

docs/zh/05-get-started/03-package.md

@@ -29,6 +29,7 @@ echo "deb [arch=amd64] http://repos.taosdata.com/tdengine-stable stable main" |
 如果安装 Beta 版需要安装包仓库
 
 ```bash
+wget -qO - http://repos.taosdata.com/tdengine.key | sudo apt-key add -
 echo "deb [arch=amd64] http://repos.taosdata.com/tdengine-beta beta main" | sudo tee /etc/apt/sources.list.d/tdengine-beta.list
 ```