Remove the Django requirement from this application

[cwdavies]

We should probably only pin Wagtail in this application, and support
the version range for Django that our Wagtail version specifies.

[coveralls]

Pull Request Test Coverage Report for Build 845

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 799:	0.0%
Covered Lines:	202
Relevant Lines:	202

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💛 - Coveralls

[cwdavies]

Wagtail 2.9 was released today, Do we want to start thinking about heading right to that instead of 2.8?

[willbarton]

This is way too broad a removal of Django. We still need to test against Django 1.11 and 2.2 (we could drop testing against 2.0).

We just do not need to specify a required version in setup.py for pip to resolve dependencies. For that we can take whatever the version of Wagtail we're using provides.

[willbarton]

This is way too broad a removal of Django. We still need to test against Django 1.11 and 2.2 (we could drop testing against 2.0).

We just do not need to specify a required version in setup.py for pip to resolve dependencies. For that we can take whatever the version of Wagtail we're using provides.