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

django-stubs/test/runner.pyi

@@ -70,7 +70,7 @@ class ParallelTestSuite(TestSuite):
     processes: Any = ...
     failfast: Any = ...
     def __init__(self, suite: Any, processes: Any, failfast: bool = ...) -> None: ...
-    def run(self, result: Any): ...  # type: ignore
+    def run(self, result: Any): ...  # type: ignore[override]
 
 class DiscoverRunner:
     test_suite: Any = ...