Allow use Django>=3.1

[ron8mcr]

• Add Django==3.1 to tox test matrix
• Remove direct Django dependency (as suggested in Potential dependency conflicts between django-reversion-compare and django #131)
• Fix pytest arguments after 6.0 released

[ron8mcr]

Sorry, build is broken, poetry and tox integration is not so simple:
python-poetry/poetry#1745

In my local environment, everything worked OK as poetry installed Django==3.0 first, and all tests in all environments was run with this version (as poetry install runs after tox prepared virtualnev).
So tests cannot be run until django-tools will be fixed

[zymergen-stian]

Any progress on this one? Due to the new stricter pip resolver, I can no longer turn a blind eye on django-reversion-compare==0.12.2 with Django>=3.1 now.

Looks like master build was failing before this PR, so should it be blocking on this change?

[nschlemm]

@jedie THX for merging this - any plans when this will be released? :)

[jedie]

thanks for the reminder ;)

It's not released as v0.13.0