Remove roadmap section from README

Removed the roadmap section and its content from the README.

Author: maninhill

README.md

@@ -55,11 +55,6 @@ docker run -d \
     <img alt="q&a" src="https://github.com/user-attachments/assets/55526514-52f3-4cfe-98ec-08a986259280"   />
   </tr>
 
-## Roadmap
-
-- SQL 示例库：开发中...
-- 自定义提示词：开发中...
-
 ## Star History
 
 [![Star History Chart](https://api.star-history.com/svg?repos=dataease/sqlbot&type=Date)](https://www.star-history.com/#dataease/sqlbot&Date)