Add Django 6.0 to trove classifiers

Author: ulgens

pyproject.toml

@@ -24,6 +24,7 @@ classifiers = [
   "Framework :: Django :: 5.0",
   "Framework :: Django :: 5.1",
   "Framework :: Django :: 5.2",
+  "Framework :: Django :: 6.0",
   "Intended Audience :: Developers",
   "License :: OSI Approved :: BSD License",
   "Programming Language :: Python",