fixed swagger API documentation for POST /tasks/{id}/data endpoint (#1963)

cvat/apps/engine/views.py

@@ -389,7 +389,9 @@ class TaskViewSet(auth.TaskGetQuerySetMixin, viewsets.ModelViewSet):
 
         return Response(serializer.data)
 
-    @swagger_auto_schema(method='post', operation_summary='Method permanently attaches images or video to a task')
+    @swagger_auto_schema(method='post', operation_summary='Method permanently attaches images or video to a task',
+        request_body=DataSerializer,
+    )
     @swagger_auto_schema(method='get', operation_summary='Method returns data for a specific task',
         manual_parameters=[
             openapi.Parameter('type', in_=openapi.IN_QUERY, required=True, type=openapi.TYPE_STRING,