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

http://greenkeeper.io/
nono/cozy-desktop,nono/cozy-desktop,cozy-labs/cozy-desktop,nono/cozy-desktop,cozy-labs/cozy-desktop,nono/cozy-desktop,kosssi/cozy-desktop,cozy-labs/cozy-desktop,cozy-labs/cozy-desktop