routedns: Add updateScript attribute

pkgs/by-name/ro/routedns/package.nix

@@ -2,6 +2,7 @@
   lib,
   buildGoModule,
   fetchFromGitHub,
+  nix-update-script,
 }:
 
 buildGoModule rec {
@@ -24,6 +25,8 @@ buildGoModule rec {
     "-w"
   ];
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     homepage = "https://github.com/folbricht/routedns";
     description = "DNS stub resolver, proxy and router";