fix link in readme (#902)

Co-authored-by: m-danilow <mdanilowski@student.agh.edu.pl>
Co-authored-by: Hervé Beraud <hberaud@redhat.com>

README.rst

@@ -33,7 +33,7 @@ the migration do not hesitate to `open a new issue`_, we will be happy to
 answer them.
 
 .. _asyncio: https://docs.python.org/3/library/asyncio.html
-.. _open_a_new_issue: https://github.com/eventlet/eventlet/issues/new
+.. _open a new issue: https://github.com/eventlet/eventlet/issues/new
 
 Eventlet
 ========