nitrokey-app: add panicgh to maintainers

pkgs/tools/security/nitrokey-app/default.nix

···
     '';
     homepage         = "https://github.com/Nitrokey/nitrokey-app";
     license          = licenses.gpl3;
-    maintainers      = with maintainers; [ kaiha ];
+    maintainers      = with maintainers; [ kaiha panicgh ];
   };
 }