protonup-qt: add zstd to extraPkgs

pkgs/applications/misc/protonup-qt/default.nix

@@ -20,6 +20,8 @@ appimageTools.wrapType2 {
       --replace 'Icon=net.davidotek.pupgui2' 'Icon=${pname}'
   '';
 
+  extraPkgs = pkgs: with pkgs; [ zstd ];
+
   meta = with lib; {
     homepage = "https://davidotek.github.io/protonup-qt/";
     description = "Install and manage Proton-GE and Luxtorpeda for Steam and Wine-GE for Lutris with this graphical user interface.";