Fix a broken link (#455)

* Fix a borken link

* Fix the cn link

docs/getting_started/installation_cn.md

@@ -100,4 +100,4 @@ python setup.py bdist_wheel
 pip install --upgrade dist/visualdl-*.whl
 ```
 
-如果打包和安装遇到其他问题，不安装只想运行Visual DL可以看[这里](https://github.com/PaddlePaddle/VisualDL/blob/develop/docs/how_to_dev_frontend_en.md)
+如果打包和安装遇到其他问题，不安装只想运行Visual DL可以看[这里](https://github.com/PaddlePaddle/VisualDL/blob/develop/docs/develop/how_to_dev_frontend_en.md)

docs/getting_started/installation_en.md

@@ -104,4 +104,4 @@ pip install --upgrade dist/visualdl-*.whl
 ```
 
 If there are still issues regarding the ```pip install```, you can still start Visual DL by starting the dev server
-[here](https://github.com/PaddlePaddle/VisualDL/blob/develop/docs/how_to_dev_frontend_en.md)
+[here](https://github.com/PaddlePaddle/VisualDL/blob/develop/docs/develop/how_to_dev_frontend_en.md)