sirula: add update script

pkgs/by-name/si/sirula/package.nix

@@ -1,4 +1,5 @@
 {
+  nix-update-script,
   lib,
   fetchFromGitHub,
   rustPlatform,
@@ -28,6 +29,8 @@ rustPlatform.buildRustPackage rec {
     gtk-layer-shell
   ];
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     description = "Simple app launcher for wayland written in rust";
     homepage = "https://github.com/DorianRudolph/sirula";