message: Add quatization support to SUM
diff: @@ -217,6 +217,11 @@ OperatorProperty GetOperatorProperty(const BuiltinOperator& op) {
  property.outputs = {{0, {}}};
  property.version = 2;
  break;
  + case BuiltinOperator_SUM:
  + property.inputs = {{0, {}}};
  + property.outputs = {{0, {}}};
  + property.version = 2;
  + break;
  case BuiltinOperator_TANH: {
  property.inputs = {{0, {}}};
  // Tanh requires output with 1/128 as scale and 0 as zero point.
  