add README.md codecov badge

Author: a-wing

README.md

@@ -4,13 +4,17 @@
 </h1>
 
 <div align="center">
-    <a href="https://live777.pages.dev/"><b>&gt;&gt;&gt; Document Is Here &lt;&lt;&lt;</b></a>
-    <br/>
-    <br/>
+  <a href="https://live777.pages.dev/guide/what-is-live777">
+    <b>Documentation</b>
+  </a>
+  |
+  <a href="https://live777.pages.dev/zh/guide/what-is-live777">
+    <b>中文文档</b>
+  </a>
 </div>
 
 <div align="center">
-
+[![codecov](https://codecov.io/gh/binbat/live777/graph/badge.svg)](https://codecov.io/gh/binbat/live777)
 [![Rust](https://github.com/binbat/live777/actions/workflows/rust.yml/badge.svg)](https://github.com/binbat/live777/actions/workflows/rust.yml)
 [![GitHub release](https://img.shields.io/github/tag/binbat/live777.svg?label=release)](https://github.com/binbat/live777/releases)