nixos/qmk: add keychron support

nixos/modules/hardware/keyboard/qmk.nix

@@ -8,15 +8,18 @@
 let
   cfg = config.hardware.keyboard.qmk;
   inherit (lib) mkEnableOption mkIf;
-
 in
 {
   options.hardware.keyboard.qmk = {
     enable = mkEnableOption "non-root access to the firmware of QMK keyboards";
+    keychronSupport = mkEnableOption "udev rules for keychron QMK based keyboards";
   };
 
   config = mkIf cfg.enable {
-    services.udev.packages = [ pkgs.qmk-udev-rules ];
+    services.udev.packages = [
+      pkgs.qmk-udev-rules
+    ]
+    ++ lib.optionals cfg.keychronSupport [ pkgs.keychron-udev-rules ];
     users.groups.plugdev = { };
   };
 }