cliphist: add update script

pkgs/by-name/cl/cliphist/package.nix

@@ -2,6 +2,7 @@
   lib,
   buildGoModule,
   fetchFromGitHub,
+  nix-update-script,
 }:
 
 buildGoModule rec {
@@ -21,6 +22,10 @@ buildGoModule rec {
     cp ${src}/contrib/* $out/bin/
   '';
 
+  passthru = {
+    updateScript = nix-update-script { };
+  };
+
   meta = with lib; {
     description = "Wayland clipboard manager";
     homepage = "https://github.com/sentriz/cliphist";