isort: Treat tc_aws and thumbor as third-party.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

.isort.cfg

@@ -1,6 +1,6 @@
 [settings]
 multi_line_output = 3
-known_third_party = netifaces
+known_third_party = netifaces, tc_aws, thumbor
 include_trailing_comma = True
 use_parentheses = True
 line_length = 100

zthumbor/loaders/zloader.py

@@ -6,11 +6,10 @@ import logging
 from typing import Any, Callable
 
 from six.moves import urllib
-from tornado.concurrent import return_future
-
 from tc_aws.loaders import s3_loader
 from thumbor.context import Context
 from thumbor.loaders import LoaderResult, file_loader, https_loader
+from tornado.concurrent import return_future
 
 from .helpers import (
     THUMBOR_EXTERNAL_TYPE,