Add Django 6 classifiers to trove_classifiers (#224)

Author: carltongibson

src/trove_classifiers/__init__.py

@@ -132,6 +132,8 @@
     "Framework :: Django :: 5.0",
     "Framework :: Django :: 5.1",
     "Framework :: Django :: 5.2",
+    "Framework :: Django :: 6",
+    "Framework :: Django :: 6.0",
     "Framework :: Django CMS",
     "Framework :: Django CMS :: 3.4",
     "Framework :: Django CMS :: 3.5",