Update Django version classifiers

Author: ArtyomVancyan

setup.cfg

@@ -36,8 +36,8 @@ classifiers =
     Framework :: Django :: 2.2
     Framework :: Django :: 3.1
     Framework :: Django :: 3.2
-    Framework :: Django :: 4.0
     Framework :: Django :: 4.1
+    Framework :: Django :: 4.2
     Programming Language :: Python
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6