Downgrade `uglify-js` version to work properly with webpack 2 (#348)
Downgrade `uglify-js` version to work properly with webpack 2 (#348)

- See https://github.com/webpack-contrib/uglifyjs-webpack-plugin/issues/32
paypal/paypal-checkout,andreabondi/paypal-checkout,bluepnume/paypal-checkout,vishakha94/paypal-checkout,andreabondi/paypal-checkout,vishakha94/paypal-checkout,trainerbill/paypal-checkout,bluepnume/paypal-checkout,vishakha94/paypal-checkout,paypal/paypal-checkout,mstuart/paypal-checkout,mstuart/paypal-checkout,trainerbill/paypal-checkout,mstuart/paypal-checkout,andreabondi/paypal-checkout,paypal/paypal-checkout,bluepnume/paypal-checkout,trainerbill/paypal-checkout