chore(django-rest-framework): upgrade to 3.9.3

rootfs/api/exceptions.py

@@ -1,9 +1,8 @@
 from django.http import Http404
 import logging
-from rest_framework.compat import set_rollback
 from rest_framework.exceptions import APIException, status
 from rest_framework.response import Response
-from rest_framework.views import exception_handler
+from rest_framework.views import set_rollback, exception_handler
 
 
 class HealthcheckException(APIException):

rootfs/api/tests/test_pods.py

@@ -392,7 +392,8 @@ def test_scale_errors(self, mock_requests):
         response = self.client.post(url, body)
         self.assertEqual(response.status_code, 400, response.data)
         self.assertEqual(response.data, {"detail": "Invalid scaling format: "
-                                         "['Must be greater than or equal to zero']"})
+                                         "[ErrorDetail(string='Must be greater "
+                                         "than or equal to zero', code='invalid')]"})
 
         # scale to something other than a number
         url = "/v2/apps/{app_id}/scale".format(**locals())

rootfs/requirements.txt

@@ -4,7 +4,7 @@ django==1.11.20
 django-auth-ldap==1.2.15
 django-cors-middleware==1.3.1
 django-guardian==1.4.9
-djangorestframework==3.6.4
+djangorestframework==3.9.3
 docker-py==1.10.6
 gunicorn==19.7.1
 idna==2.6