Update util-sass-compiler to use dart-sass

[alexkilgour]

Currently awaiting a fix for sass issues within Jest. See more detail in pull request #74

[alexkilgour]

Could we sandbox running SASS using something like: https://github.com/breejs/bree/

[alexkilgour]

Issue also opened here regarding potential fix
https://github.com/kayahr/jest-environment-node-single-context/issues/8