clusterctl: remove maintainer

pkgs/applications/networking/cluster/clusterctl/default.nix

···
     description = "Kubernetes cluster API tool";
     homepage = "https://cluster-api.sigs.k8s.io/";
     license = licenses.asl20;
-    maintainers = with maintainers; [ zowoq qjoly ];
+    maintainers = with maintainers; [ qjoly ];
   };
 }