diskonaut: add SuperSandro2000 as maintainer

pkgs/tools/misc/diskonaut/default.nix

···
     description = "Terminal disk space navigator";
     homepage = "https://github.com/imsnif/diskonaut";
     license = licenses.mit;
-    maintainers = with maintainers; [ evanjs ];
+    maintainers = with maintainers; [ evanjs SuperSandro2000 ];
   };
 }