improve changelog

Author: cp-bagerard

docs/changelog.rst

@@ -6,11 +6,12 @@ Changelog
 Development
 ===========
 - (Fill this out as you fix issues and develop your features).
-- Bug fix in DynamicDocument which isn not parsing known fields in constructor like Document do #2412
+- Bug fix in DynamicDocument which is not parsing known fields in constructor like Document do #2412
 - When using pymongo >= 3.7, make use of Collection.count_documents instead of Collection.count
     and Cursor.count that got deprecated in pymongo >= 3.7.
     This should have a negative impact on performance of count see Issue #2219
 - Fix a bug that made the queryset drop the read_preference after clone().
+- Remove Py3.5 from CI as it reached EOL and add Python 3.9
 - Fix the behavior of Doc.objects.limit(0) which should return all documents (similar to mongodb) #2311
 - Bug fix in ListField when updating the first item, it was saving the whole list, instead of
     just replacing the first item (as it's usually done) #2392