Remove dependency on django.utils.six

[jsocol]

django.utils.six is gone in 3.0. It's still present in 2.2 but we should remove the dependency. We can consider this along with ESRs and Python2 support

[JBKahn]

Any support for this? Would you accept PRs?

[jsocol]

I would absolutely accept a PR.

At this point, I think it's probably fine to drop Python2 support and to build it in such a way that is Py3-only—which is hopefully fairly straightforward. It's more a question now of what that means the next released version will be.

[JBKahn]

Up to you. I'd say dropping Python 2 is a major version bump but I'm not sure.

[JBKahn]

Here's all I have #47

[timwilson]

@jsocol Is the Django 3 compatibility forthcoming? I'd love to use this package on my project.