run black over stubs, add checking to travis

django-stubs-generated/contrib/auth/handlers/modwsgi.pyi

@@ -2,7 +2,5 @@ from typing import Any, Dict, Optional
 
 UserModel: Any
 
-def check_password(
-    environ: Dict[Any, Any], username: str, password: str
-) -> Any: ...
+def check_password(environ: Dict[Any, Any], username: str, password: str) -> Any: ...
 def groups_for_user(environ: Dict[Any, Any], username: str) -> Any: ...