intel-undervolt: add nix-update-script

pkgs/by-name/in/intel-undervolt/package.nix

@@ -2,6 +2,7 @@
   lib,
   stdenv,
   fetchFromGitHub,
+  nix-update-script,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -24,6 +25,8 @@ stdenv.mkDerivation (finalAttrs: {
     runHook postInstall
   '';
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     description = "Intel CPU undervolting and throttling configuration tool";
     homepage = "https://github.com/kitsunyan/intel-undervolt";