Bump django-extensions from 2.1.7 to 2.2.8

Bumps [django-extensions](https://github.com/django-extensions/django-extensions) from 2.1.7 to 2.2.8.
- [Release notes](https://github.com/django-extensions/django-extensions/releases)
- [Changelog](https://github.com/django-extensions/django-extensions/blob/master/CHANGELOG.md)
- [Commits](https://github.com/django-extensions/django-extensions/compare/2.1.7...2.2.8

)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements.txt

@@ -10,7 +10,7 @@ django-anymail==7.0.0
 django-basic-auth-ip-whitelist==0.3.1
 django-bleach==0.6.1
 django-countries==5.5
-django-extensions==2.1.7
+django-extensions==2.2.8
 django-filter==2.2.0
 django-fsm==2.6.1
 django-heroku==0.3.1