www/py-django-extensions: Update to 2.2.9

• Assign the port to Django 2.2 (current LTS release) as Django 1.11 is End-of-Life since April.

Changelog:

https://github.com/django-extensions/django-extensions/blob/2.2.9/CHANGELOG.md

PR: 245357
Reviewed by: wen
Approved by: Kevin Golding <ports@caomhin.org> (maintainer)