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

pytest.ini

@@ -1,11 +1,10 @@
 [pytest]
 testpaths =
-    ./test-plugin
-    ./test-data
+    ./tests
 addopts =
     --tb=native
     -s
     -v
     --cache-clear
-    --mypy-ini-file=./test-data/plugins.ini
+    --mypy-ini-file=./tests/plugins.ini
     --mypy-extension-hook=scripts.tests_extension_hook.django_plugin_hook