Update doc/whatsnew/index.rst

Co-authored-by: Daniël van Noord <[email protected]>

Author: Pierre-Sassoulas

doc/whatsnew/index.rst

@@ -25,7 +25,7 @@ High level descriptions of the most important changes between major Pylint versi
    2.1.rst
    2.0.rst
 
-Python 2 compatible version
+Python 2 compatible versions
 ---------------------------
 
 .. toctree::