Update the version of SIGN operator in reference resolver.

Version 1 and 2 are supported by the kernel used by the reference resolver.

PiperOrigin-RevId: 775468100

Author: majiddadashi

tflite/kernels/register_ref.cc

@@ -539,7 +539,9 @@ BuiltinRefOpResolver::BuiltinRefOpResolver() {
   AddBuiltin(BuiltinOperator_UNSORTED_SEGMENT_SUM,
              Register_UNSORTED_SEGMENT_SUM());
   AddBuiltin(BuiltinOperator_ATAN2, Register_ATAN2());
-  AddBuiltin(BuiltinOperator_SIGN, Register_SIGN());
+  AddBuiltin(BuiltinOperator_SIGN, Register_SIGN(),
+             /* min_version = */ 1,
+             /* max_version = */ 2);
   AddBuiltin(BuiltinOperator_CALL_ONCE,
              tflite::ops::builtin::Register_CALL_ONCE());
   AddBuiltin(BuiltinOperator_VAR_HANDLE, Register_VAR_HANDLE());