title: Use a different shareable config for eslint in a subfolder of a project
body: <p>I have a node 8 project in ES6, that also contains some client-side code in ES5. I'm linting the node code with eslint and using airbnb-base for it.</p>
  
  <p>However, the client-side code is ES5, so I want to use airbnb-base/legacy for it. The problem is that the ES5 client-side code is in a subfolder of the project, which automatically inherits the main eslint configuration (so also the <code>extends: ["airbnb-base"]</code>.</p>
  
  <p>Is there a way to specify <code>extends: ["airbnb-base/legacy"]</code> for folder below the main config, and not inherit <code>airbnb-base</code>?</p>