Add Django 5.2 support to django-rest-framework-jwt

[abubakarkhawaja]

Changes:

• Updated dependencies to support Django 5.2 , djangorestframework 3.16 and Python 3.11/3.12.
• Removed support for older versions of Django and Python (e.g., Python 2.7, Django < 5.2).
• Fixed timezone handling in tests by replacing timezone.now() with django_timezone.now()
• Removed deprecated imports and compatibility layers for older Django versions.
• Removed six package