updated package setup (#485)

* updated package setup

* updated to use python 3.9

* fixed test runner

* fixed typecheck tests

* fixed discrepencies

* added override to runner

* updated travis

* updated pre-commit hooks

* updated dep

mypy.ini

@@ -1,2 +1,14 @@
 [mypy]
-warn_unused_ignores = True
+strict_optional = True
+ignore_missing_imports = True
+check_untyped_defs = True
+warn_no_return = False
+show_traceback = True
+allow_redefinition = True
+incremental = True
+
+plugins =
+    mypy_django_plugin.main
+
+[mypy.plugins.django-stubs]
+django_settings_module = scripts.django_tests_settings