prepare for 3.1.1 and remove py2 universal wheel

Author: jeking3

CHANGES.rst

@@ -5,6 +5,16 @@ Unreleased
 ----------
 
 
+3.1.1 (2022-04-23)
+------------------
+
+Full list of changes:
+
+- Fix py36 references in pyproject.toml (gh-960)
+- Fix local setup.py install versioning issue (gh-960)
+- Remove py2 universal wheel cfg - only py3 needed now (gh-960)
+
+
 3.1.0 (2022-04-09)
 ------------------