se agrego metodo patch

@@ -14,7 +14,6 @@ from .utils import contador
 
 class EdictoViewSet(mixins.CreateModelMixin,
                     mixins.RetrieveModelMixin,
-                    mixins.UpdateModelMixin,
                     mixins.ListModelMixin,
                     viewsets.GenericViewSet):
 
@@ -36,10 +35,9 @@ class EdictoViewSet(mixins.CreateModelMixin,
                         usuario_movimiento=usuario,
                         )
 
-    @action(detail=True, methods=['patch'])
-    def custom_update(self, request):
+    def partial_update(self, request):
         instance = self.get_object()
-        serializer = self.get_serializer(instance, data=request.data)
+        serializer = self.get_serializer(instance, data=request.data, partial=True)
         serializer.is_valid(raise_exception=True)
 
         edicto = request.data.get('cuerpo_edicto')