Describe the bug

Updating the dependency version in the package.json file then running yarn does not update the referenced bootstrap version

Normalise.css is also included in the packages.json but is not added to the dist/css folder. This is not as much of an issue as it's not referenced in the includes.ascx

To Reproduce

Steps to reproduce the behavior:

1. extract nvQuickTheme zip to folder
2. Update Bootstrap version in package.json from 4.0.0. to ^4.1.0
3. run yarn
4. package in node_modules is updated to 4.1.x but the scss files in the assets folder, which the gulp build tasks uses, is not updated.