Fix links.

README.md

@@ -25,7 +25,7 @@ Sky Walking | [中文](README_ZH.md)
 <img src="https://skywalkingtest.github.io/page-resources/3.x-architecture.jpg"/>
 
 # Document
-[![EN doc](https://img.shields.io/badge/document-English-blue.svg)](README.md) [![cn doc](https://img.shields.io/badge/document-中文-blue.svg)](README_ZH.md)
+[![EN doc](https://img.shields.io/badge/document-English-blue.svg)](docs/README.md) [![cn doc](https://img.shields.io/badge/document-中文-blue.svg)](docs/README_ZH.md)
 
 This project adheres to the Contributor Covenant [code of conduct](CODE_OF_CONDUCT.md). By participating, you are expected to uphold this code. Please report unacceptable behavior to wu.sheng@foxmail.com.
 

README_ZH.md

@@ -28,7 +28,7 @@ Sky Walking | [English](README.md)
 <img src="https://skywalkingtest.github.io/page-resources/3.x-architecture.jpg"/>
 
 # Document
-[![EN doc](https://img.shields.io/badge/document-English-blue.svg)](README.md) [![cn doc](https://img.shields.io/badge/document-中文-blue.svg)](README_ZH.md)
+[![EN doc](https://img.shields.io/badge/document-English-blue.svg)](docs/README.md) [![cn doc](https://img.shields.io/badge/document-中文-blue.svg)](docs/README_ZH.md)
 
 This project adheres to the Contributor Covenant [code of conduct](CODE_OF_CONDUCT.md). By participating, you are expected to uphold this code. Please report unacceptable behavior to wu.sheng@foxmail.com.