[Fix] Fix sphinx compile error (#1176)

* [Docs] Fix sphinx version

* [Docs] Remove sphinx_markdown_tables

* update readme link

* add sphinx_rtd_theme package

README.md

@@ -170,14 +170,14 @@ pip install mmcv
 
 c. Install full version with custom operators for onnxruntime
 
-- Check [here](docs/onnxruntime_op.md) for detailed instruction.
+- Check [here](docs/deployment/onnxruntime_op.md) for detailed instruction.
 
-If you would like to build MMCV from source, please refer to the [guide](https://mmcv.readthedocs.io/en/latest/build.html).
+If you would like to build MMCV from source, please refer to the [guide](https://mmcv.readthedocs.io/en/latest/get_started/build.html).
 
 ## FAQ
 
 If you face some installation issues, CUDA related issues or RuntimeErrors,
-you may first refer to this [Trouble Shooting Page](https://mmcv.readthedocs.io/en/latest/trouble_shooting.html).
+you may first refer to this [Frequently Asked Questions](https://mmcv.readthedocs.io/en/latest/faq.html).
 
 ## Citation
 

README_zh-CN.md

@@ -167,13 +167,13 @@ pip install mmcv
 
 c. 安装完整版并且编译 onnxruntime 的自定义算子
 
-- 详细的指南请查看 [这里](docs/onnxruntime_op.md)。
+- 详细的指南请查看 [这里](docs/deployment/onnxruntime_op.md)。
 
-如果想从源码编译 MMCV，请参考[该文档](https://mmcv.readthedocs.io/en/latest/build.html)。
+如果想从源码编译 MMCV，请参考[该文档](https://mmcv.readthedocs.io/en/latest/get_started/build.html)。
 
 ## FAQ
 
-如果你遇到了安装问题，CUDA 相关的问题或者 RuntimeErrors，可以首先参考[问题解决页面](https://mmcv.readthedocs.io/en/latest/trouble_shooting.html) 看是否已经有解决方案。
+如果你遇到了安装问题，CUDA 相关的问题或者 RuntimeErrors，可以首先参考[问题解决页面](https://mmcv.readthedocs.io/en/latest/faq.html) 看是否已经有解决方案。
 
 ## 贡献指南
 

requirements/docs.txt

 m2r
 opencv-python
-sphinx==3.1.2
+sphinx
 sphinx_markdown_tables
+sphinx_rtd_theme
 torch