build: update Node.js logo on OSX installer

PR-URL: nodejs#5401
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: kahwee
Reviewed-By: fhemberger
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

Author: rvagg