doc: update README.md

Author: jaywcjlove

README.md

@@ -600,6 +600,7 @@ Quick Reference
 非常感谢那些一直支持我开源工作的朋友们。如果您对我的工作感到满意，可以选择在[这里进行赞助](https://wangchujiang.com/#/sponsor)<!--rehype:target=_blank-->。也可以通过下载并使用我开发的 [macOS 应用](https://wangchujiang.com/#/app)<!--rehype:target=_blank-->来支持我。以下是我个人开发的 macOS 应用：
 
 <p style="display: inline-block">
+  <a target="_blank" href="https://wangchujiang.com/file-sentinel/" title="FileSentinel for macOS"><img align="center" alt="FileSentinel" height="52" width="52" src="./appicon/file-sentinel.png"></a>
   <a target="_blank" href="https://wangchujiang.com/focus-cursor/" title="FocusCursor for macOS"><img align="center" alt="FocusCursor" height="52" width="52" src="./appicon/focus-cursor.png"></a>
   <a target="_blank" href="https://wangchujiang.com/videoer/" title="Videoer for macOS"><img align="center" alt="Videoer" height="52" width="52" src="./appicon/videoer.png"></a>
   <a target="_blank" href="https://wangchujiang.com/key-clicker/" title="KeyClicker for macOS"><img align="center" alt="KeyClicker" height="50" width="50" src="./appicon/key-clicker.png"></a>