Add django 4.1 support

[Khatskevich]

Wagtail now supports Django 4.1. For some users wagtail-grapple may be the last dependency which prevents from updating Django.

It will be nice to have support Django 4.1.

[jams2]

This appears to be due to graphene-django being incompatible with Django 4 (4.1?).

graphene-django appears to be unmaintained. See also https://github.com/graphql-python/graphene-django/issues/1324#issuecomment-1140494403.

This will probably also affect https://github.com/torchbox/wagtail-grapple/pull/143

[PeterDekkers]

graphene-django v3.0.0 was just released, which adds Django 4 support.

https://github.com/graphql-python/graphene-django/releases/tag/v3.0.0

Relevant PR: https://github.com/graphql-python/graphene-django/pull/1281

[zerolab]

cross-posted to #143.