doc: fix broken newsfragment link in contributing

Author: acul71

docs/contributing.rst

@@ -294,7 +294,7 @@ do not pass the CI build yet won't get reviewed unless explicitly requested.
 
 If the pull request introduces changes that should be reflected in the release notes,
 please add a newsfragment file as explained
-`here <https://github.com/ethereum/py-libp2p/blob/main/newsfragments/README.md>`_.
+`here <https://github.com/libp2p/py-libp2p/tree/main/newsfragments>`_.
 
 If possible, the change to the release notes file should be included in the commit that
 introduces the feature or bugfix.