chore(package): update gulp to version 3.9.1
chore(package): update gulp to version 3.9.1

http://greenkeeper.io/
MozaikAgency/wp-theme-starter,usine/wp-usine,juandak16/wp-theme-starter,juandak16/wp-theme-starter,usine/wp-usine,MozaikAgency/wp-theme-starter,champagne-randy/wp-theme-bootstrap,MozaikAgency/wp-theme-bootstrap,tylershuster/wp-theme-starter,MozaikAgency/wp-theme-bootstrap,tylershuster/wp-theme-starter,champagne-randy/wp-theme-bootstrap