chore(package): update babel-preset-es2015 to version 6.13.1 (#893)
chore(package): update babel-preset-es2015 to version 6.13.1 (#893)

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mozilla/addons-frontend,aviarypl/mozilla-l10n-addons-frontend,mstriemer/addons-frontend,muffinresearch/addons-frontend,kumar303/addons-frontend,kumar303/addons-frontend,kumar303/addons-frontend,jasonthomas/addons-frontend,squarewave/addons-frontend,tsl143/addons-frontend,aviarypl/mozilla-l10n-addons-frontend,muffinresearch/addons-frontend,mstriemer/addons-frontend,mozilla/addons-frontend,kumar303/addons-frontend,aviarypl/mozilla-l10n-addons-frontend,tsl143/addons-frontend,tsl143/addons-frontend,mozilla/addons-frontend,squarewave/addons-frontend,tsl143/addons-frontend,mozilla/addons-frontend,muffinresearch/addons-frontend,jasonthomas/addons-frontend,mstriemer/addons-frontend,aviarypl/mozilla-l10n-addons-frontend,jasonthomas/addons-frontend,squarewave/addons-frontend