Remove util in README.md
Remove util in README.md

`util` is not used.
jean-emmanuel/yargs,nexdrew/yargs,elas7/yargs,tepez/yargs,geophree/yargs,elas7/yargs,geophree/yargs,yargs/yargs,yargs/yargs,yargs/yargs,jean-emmanuel/yargs,tepez/yargs,bcoe/yargs,bcoe/yargs,nexdrew/yargs