chore(package): update babel-loader to version 6.4.1
chore(package): update babel-loader to version 6.4.1

Closes #1972

https://greenkeeper.io/

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