Update README.md

Author: overtrue

README.md

@@ -82,6 +82,12 @@ $url = $disk->privateDownloadUrl('folder/my_file.txt');
 
 [Full API documentation.](http://flysystem.thephpleague.com/api/)
 
+## :heart: Sponsor me 
+
+If you like the work I do and want to support it, [you know what to do :heart:](https://github.com/sponsors/overtrue)
+
+如果你喜欢我的项目并想支持它，[点击这里 :heart:](https://github.com/sponsors/overtrue)
+
 ## PHP 扩展包开发
 
 > 想知道如何从零开始构建 PHP 扩展包？