[3.9] bpo-34003: Re-add versionchanged entry in csv docs (GH-20657) (GH-20770)

Follow-up to GH-8014 (cherry picked from commit 7aed052) Co-authored-by: Éric Araujo <merwok@netwok.org> Automerge-Triggered-By: @merwok

Author: miss-islington

Doc/library/csv.rst

@@ -167,6 +167,9 @@ The :mod:`csv` module defines the following classes:
  All other optional or keyword arguments are passed to the underlying
  :class:`reader` instance.
 
+ .. versionchanged:: 3.6
+ Returned rows are now of type :class:`OrderedDict`.
+
  .. versionchanged:: 3.8
  Returned rows are now of type :class:`dict`.