Update to Django 2.2
Closes #855 (closed)
Short description
Update to Django 2.2
- Pin the versions of dependencies to semver patch.
- Change the content type of proxy model permissions (https://github.com/django/django/commit/181fb60159e54d442d3610f4afba6f066a6dac05)
Edited by Sébastiaan Versteeg