chore: Update README

Author: whale4113

README.md

@@ -7,6 +7,8 @@
 
 Cloud Document Converter is a browser extension that supports downloading/copying Lark Doc as Markdown.
 
+**English** · [简体中文](./README_ZH.md)
+
 # Install
 
 Install Cloud Document Converter from [Chrome Web Store](https://chromewebstore.google.com/detail/cloud-document-converter/ehkomhhcinhikfddnmklbloahaakploh), [Microsoft Edge Store](https://microsoftedge.microsoft.com/addons/detail/pcjebkebnehplnpkpnhipagefaffiopp), and [Firefox Add-ons Store](https://addons.mozilla.org/addon/cloud-document-converter).

README_ZH.md

@@ -7,6 +7,8 @@
 
 Cloud Document Converter 是一个浏览器扩展， 支持下载、复制飞书云文档为 Markdown。
 
+[English](./README.md) · **简体中文**
+
 # 安装
 
 从 [Chrome 应用商店](https://chromewebstore.google.com/detail/cloud-document-converter/ehkomhhcinhikfddnmklbloahaakploh)、[Microsoft Edge 加载项](https://microsoftedge.microsoft.com/addons/detail/pcjebkebnehplnpkpnhipagefaffiopp) 和 [Firefox 附加组件](https://addons.mozilla.org/addon/cloud-document-converter) 安装 Cloud Document Converter。