refactor(api): make SerialListView more idiomatic

api/desecapi/urls/version_1.py

@@ -42,7 +42,7 @@ api_urls = [
     path('dyndns/update', views.DynDNS12UpdateView.as_view(), name='dyndns12update'),
 
     # Serials
-    path('serials/', views.SerialList.as_view(), name='serial'),
+    path('serials/', views.SerialListView.as_view(), name='serial'),
 
     # Donation
     path('donation/', views.DonationList.as_view(), name='donation'),

api/desecapi/views.py

@@ -169,11 +169,11 @@ class DomainViewSet(IdempotentDestroyMixin,
                 parent_domain.update_delegation(instance)
 
 
-class SerialList(generics.ListAPIView):
+class SerialListView(APIView):
     permission_classes = (IsVPNClient,)
     throttle_classes = []  # don't break slaves when they ask too often (our cached responses are cheap)
 
-    def list(self, request, *args, **kwargs):
+    def get(self, request, *args, **kwargs):
         key = 'desecapi.views.serials'
         serials = cache.get(key)
         if serials is None: