Officially Support Django 5.0

[vrocha]

Currently, django-password-reset supports Django 3.0+ and Python 3+. To ensure compatibility with Django 5.0, we need to update the project configuration and documentation.

Tasks:

Update tox.ini to add Django 5.0 to the test matrix. Include a new test environment [testenv:py{39,310}-django50] with dependencies Django>=5.0,<6.0, pytest, and pytest-django.

Run tests using tox to ensure compatibility with Django 5.0. Use the command tox -e py39-django50,py310-django50.

Update documentation (e.g., README) to include Django 5.0 as a supported version. Update the compatibility section to say: "Compatibility: Django 3.2, 4.2, and 5.0."

Update setup.py to reflect compatibility with Django 5.0 in the classifiers. Add Framework :: Django :: 5.0 and ensure other versions are listed accurately.