Make view async for django.

graphene_django/views.py

@@ -9,6 +9,7 @@
 from django.http.response import HttpResponseBadRequest
 from django.shortcuts import render
 from django.utils.decorators import classonlymethod, method_decorator
+from django.utils.functional import classproperty
 from django.views.decorators.csrf import ensure_csrf_cookie
 from django.views.generic import View
 from graphql import (
@@ -497,6 +498,10 @@ def as_view(cls, **initkwargs):
         view._is_coroutine = coroutines._is_coroutine
         return view
 
+    @classproperty
+    def view_is_async(cls):
+        return True
+
     async def dispatch(self, request, *args, **kwargs):
         try:
             if request.method.lower() not in ("get", "post"):