diff2html-cli: add updateScript

pkgs/by-name/di/diff2html-cli/package.nix

@@ -7,6 +7,7 @@
   yarnBuildHook,
   yarnInstallHook,
   nodejs,
+  nix-update-script,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -37,6 +38,8 @@ stdenv.mkDerivation (finalAttrs: {
     nodejs
   ];
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     description = "Generate pretty HTML diffs from unified and git diff output in your terminal";
     homepage = "https://diff2html.xyz#cli";