zopfli: removed roconnor as a maintainer

roconnor was added as a maintainer by accident

pkgs/tools/compression/zopfli/default.nix

···
       '';
     platforms = stdenv.lib.platforms.linux;
     license = stdenv.lib.licenses.asl20;
-    maintainers = with maintainers; [ roconnor bobvanderlinden ];
+    maintainers = with maintainers; [ bobvanderlinden ];
   };
 }