speakersafetyd: add nix-update-script

pkgs/by-name/sp/speakersafetyd/package.nix

@@ -6,6 +6,7 @@
   pkg-config,
   alsa-lib,
   udevCheckHook,
+  nix-update-script,
 }:
 
 rustPlatform.buildRustPackage (finalAttrs: {
@@ -46,6 +47,10 @@ rustPlatform.buildRustPackage (finalAttrs: {
   dontCargoInstall = true;
   doInstallCheck = true;
 
+  passthru = {
+    updateScript = nix-update-script { };
+  };
+
   meta = {
     description = "Userspace daemon that implements the Smart Amp protection model";
     mainProgram = "speakersafetyd";