gping: add nix update script

pkgs/tools/networking/gping/default.nix

@@ -6,6 +6,7 @@
   installShellFiles,
   iputils,
   versionCheckHook,
+  nix-update-script,
 }:
 
 rustPlatform.buildRustPackage rec {
@@ -42,6 +43,8 @@ rustPlatform.buildRustPackage rec {
 
   versionCheckProgramArg = [ "--version" ];
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     description = "Ping, but with a graph";
     homepage = "https://github.com/orf/gping";