cache issue

[saxxi]

Hi, first thanks for your work.

It seems there is a bug where when an imported file is changed in development mode the system is not able to catch the change.

Steps to reproduce:

1. start with yarn dev
2. see output on browser
3. change anything on styles/base.layout.scss
4. changes are not affected on browser
5. change anything on styles/style.scss
6. now changes on #3 are visible on browser

I've created a PR to test this.