fix error

Author: OliverKoo

ghapp/ghapp/cattrs.py

@@ -52,7 +52,7 @@ def _register_ignore_optional_none(cls, converter=None):
     prev_unstructure = converter._unstructure_func.dispatch(cls)
     optional_attrs = {
         f.name for f in attr.fields(cls)
-        if sys.version_info[0] <= 3 and sys.version_info[1] < 7:
+        if (sys.version_info[0] <= 3) and (sys.version_info[1] < 7):
             if isinstance(f.type, typing._Union) and type(None) in f.type.__args__
         else:
             if isinstance(f.type, typing._GenericAlias) and type(None) in f.type.__args__