doc: update fansworld-claudio username on README

Updating collaborator username: fansworld-claudio
changed to claudiorodriguez

PR-URL: https://github.com/nodejs/node/pull/5680


Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>