Create `webpackConfig` field in `vulmix.config.ts`

[Victor Ribeiro]

It should work like this:

import { VulmixConfig } from '../types/vulmix-config'

module.exports = <VulmixConfig>{
  webpackConfig: {
    resolve: {
      alias: {
        // Should add the `@libs` alias
        '@libs': `${vulmix.globals.projectRootPath}/libs`
      }
    }
  }
}