Fix link

Author: fayazkhan

README.rst

@@ -270,7 +270,7 @@ If you have any questions:
 * Contact the maintainer via email: fayaz.yusuf.khan@gmail.com
 * Contact the author via email: sacrud@uralbash.ru or #sacrud IRC channel |IRC Freenode|
 
-Refer the detailed contribution guide in the `docs <https://sqlalchemy-mptt.readthedocs.io/en/latest/CONTRIBUTING.html>`_
+Refer the detailed contribution guide in the `docs <https://sqlalchemy-mptt.readthedocs.io/CONTRIBUTING.html>`_
 for more information on setting up the development environment, running tests, and contributing to the project.
 
 License