Add Django PyPi classifiers

Author: codingjoe

setup.cfg

@@ -20,6 +20,8 @@ classifier =
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Framework :: Django
+    Framework :: Django :: 2.2
+    Framework :: Django :: 3.0
 
 [options]
 include_package_data = True