This PR cleans up code that was handling now-unsupported versions of Django and adds a proper Django middleware integration test that actually tests against the Django middleware stack.
Also expands Travis test matrix coverage to include Python 3.8 and Django 3.0 and bumps tested Django versions to only those currently officially supported - 1.11.29 LTS, 2.2.11 LTS, and the current version 3.0.4.
This PR cleans up code that was handling now-unsupported versions of Django and adds a proper Django middleware integration test that actually tests against the Django middleware stack.
Also expands Travis test matrix coverage to include Python 3.8 and Django 3.0 and bumps tested Django versions to only those currently officially supported - 1.11.29 LTS, 2.2.11 LTS, and the current version 3.0.4.