Update django-extensions to 2.2.2

[pyup-bot]

This PR updates django-extensions from 2.2.1 to 2.2.2.

Changelog

2.2.2

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Changes:
- Fix: autoslugfield, find unique method overrideable
- Fix: notes, do not replace dot in template dirs
- Fix: admin widgets, fix import of static template tag
- Improvement: print_user_for_session, use session backend
- Improvement: sqlcreate, postgis support
- Improvement: graph_models, permit combination of includes and excludes
- Improvement: Adds missing GIS engine to DEFAULT_MYSQL_ENGINES
- Improvement: sqldiff, use lowercase field names in MySQL
- Improvement: sqldiff, mysql code could duplicate AUTO_INCREMENT and UNSIGNED statements

Links

• PyPI: https://pypi.org/project/django-extensions
• Changelog: https://pyup.io/changelogs/django-extensions/
• Repo: http://github.com/django-extensions/django-extensions

[coveralls]

Coverage remained the same at 96.717% when pulling 9a8069e on pyup-update-django-extensions-2.2.1-to-2.2.2 into 669594a on master.

[pyup-bot]

Closing this in favor of #229