fix: Fix broke 'get_choices' with restframework 3.15.0 (#1506)

graphene_django/converter.py

@@ -1,5 +1,4 @@
 import inspect
-from collections import OrderedDict
 from functools import partial, singledispatch, wraps
 
 from django.db import models
@@ -72,8 +71,13 @@ def convert_choice_name(name):
 
 def get_choices(choices):
     converted_names = []
-    if isinstance(choices, OrderedDict):
+
+    # In restframework==3.15.0, choices are not passed
+    # as OrderedDict anymore, so it's safer to check
+    # for a dict
+    if isinstance(choices, dict):
         choices = choices.items()
+
     for value, help_text in choices:
         if isinstance(help_text, (tuple, list)):
             yield from get_choices(help_text)