Evaluate deprecated dependencies

[michaelnisi]

I know we’re using Yarn—why again? But still, should the deprecated dependencies called out by npm i be evaluated?

npm WARN deprecated jscs-preset-wikimedia@1.0.1: Deprecated in favour of eslint-config-wikimedia. -- https://phabricator.wikimedia.org/T118941
npm WARN deprecated nomnom@1.8.1: Package no longer supported. Contact support@npmjs.com for more info.
npm WARN deprecated text-encoding@0.6.4: no longer maintained

Travis uses npm to install.

Node.js v11.1.0