Bump ghaf to fix gen12 GUI not loading issue

Signed-off-by: Vunny Sodhi <[email protected]>

Author: vunnyso

flake.nix

@@ -30,7 +30,7 @@
 
     ghaf = {
       #url = "flake:mylocalghaf";
-      url = "github:tiiuae/ghaf";
+      url = "github:tiiuae/ghaf/28587de31b7f799424e047026927ea8207efd958";
       inputs.nixpkgs.follows = "nixpkgs";
     };