Dependencies fail to build with Node v12 on MacOS High Sierra

[jcayzac]

Some dependencies may need to be updated: fsevents, node-sass and sharp fail to build on Node 12. Downgrading to 10 has everything installing fine.

[coffeepostal]

Bumping this, it's still an issue.

[seangwright]

Also broken on Windows with Node 12 due to old packages.

This should really be brought up to the latest, some of the deps are pretty old, and this problem is just going to get worse.