Bootstrap step in instructs results in broken webpack.mix.js

[baradhili]

running php artisan grafite:bootstrap and then npm install and then npm run dev chokes on problems in webpack.js

specially `...

cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js

/home/vagrant/code/node_modules/webpack-cli/bin/cli.js:235
throw err;
^

TypeError: Cannot read property 'js' of undefined
at Object. (/home/vagrant/code/webpack.mix.js:14:5)
...
`

turns out in the grafite:bootstrap step webpack.mix.js was changed.. it became
const { mix } = require('laravel-mix');

it should be const mix = require('laravel-mix');