Add Tips to fix ESLint import/no-unresolved rule

[FredericRuaudel]

Since I use ESLint plugin eslint-plugin-import I add trouble with the rule import/no-unresolved with this plugin. So I created a resolver to fix it and publish it on npm with the name eslint-import-resolver-babel-root-slash-import.

So I propose to update your Readme to inform your users that this plugin exists, if you are ok with this ?