Consider updating clients first before making changes to this repo

[mcmire]

Extension, mobile, and core are behind the current version of our ESLint packages to varying degrees, and the chance that upgrading ESLint or enabling a previously disabled rule will cause numerous lint violations is fairly high. As raised by @legobeat, we shouldn't add any new rules or make any modifications to existing rules until we bring them up to date. If we want to introduce a new rule to a project, we should consider only enabling it there and not on an org level.