chore(package): update babel-core to version 6.23.1
chore(package): update babel-core to version 6.23.1

https://greenkeeper.io/

aviarypl/mozilla-l10n-addons-frontend,tsl143/addons-frontend,mozilla/addons-frontend,kumar303/addons-frontend,tsl143/addons-frontend,kumar303/addons-frontend,kumar303/addons-frontend,aviarypl/mozilla-l10n-addons-frontend,tsl143/addons-frontend,mozilla/addons-frontend,aviarypl/mozilla-l10n-addons-frontend,aviarypl/mozilla-l10n-addons-frontend,kumar303/addons-frontend,tsl143/addons-frontend,mozilla/addons-frontend,mozilla/addons-frontend