docs: edit incorrect link.

Author: leeqvip

README.md

@@ -222,7 +222,7 @@ Determines whether a user has a permission.
 Enforcer::hasPermissionForUser('eve', 'articles', 'read');  // true or false
 ```
 
-See [Casbin API](https://casbin.org/docs/en/management-api) for more APIs.
+See [Casbin API](https://casbin.org/docs/management-api#reference) for more APIs.
 
 ### Using a middleware