It required converting mocha tests code into async since [@wdio/sync is
deprecated](https://webdriver.io/docs/sync-vs-async/) starting with
node v16.
It removed the dependency on fibers and on [node-gyp + python](https://
webdriver.io/docs/sync-vs-async/#common-issues-in-sync-mode) indirectly
though which is a great thing.
Also moved away from node-sass to sass since [node-sass is deprecated]
(https://sass-lang.com/blog/libsass-is-deprecated).
Filip Proborszcz