attempt to add flake8 and isort

mypy_django_plugin/transformers/migrations.py

@@ -4,6 +4,7 @@ from mypy.checker import TypeChecker
 from mypy.nodes import Expression, StrExpr, TypeInfo
 from mypy.plugin import MethodContext
 from mypy.types import Instance, Type, TypeType
+
 from mypy_django_plugin import helpers