invidious-router: add `updateScript`

pkgs/by-name/in/invidious-router/package.nix

···
   lib,
   buildGoModule,
   fetchFromGitLab,
+  nix-update-script,
 }:
 let
   version = "1.2";
···
   };
 
   vendorHash = "sha256-c03vYidm8SkoesRVQZdg/bCp9LIpdTmpXdfwInlHBKk=";
+
+  passthru.updateScript = nix-update-script { };
 
   doCheck = true;