Reads in JS, returns the imported/required file paths.
// foo.scss
@import 'z';
@import 'a';
@import './a';
import thatDependsJS from 'that-depends-scss'
const fooSource = fs.readFileSync('foo.js', 'utf8')
const dependenciesOfFoo = thatDependsSCSS(fooSource)
TODO
// returns ['./a', 'a', 'z']