QS8 Sigmoid operator

PiperOrigin-RevId: 395713278
diff --git a/src/xnnpack/operator.h b/src/xnnpack/operator.h
index 13af8e1..d73b6fb 100644
--- a/src/xnnpack/operator.h
+++ b/src/xnnpack/operator.h
@@ -90,6 +90,7 @@
   xnn_operator_type_resize_bilinear_nchw_f32,
   xnn_operator_type_resize_bilinear_nhwc_f32,
   xnn_operator_type_sigmoid_nc_f32,
+  xnn_operator_type_sigmoid_nc_qs8,
   xnn_operator_type_sigmoid_nc_qu8,
   xnn_operator_type_softmax_nc_f32,
   xnn_operator_type_softmax_nc_qu8,