Use for-await

[sindresorhus]

When it's in a Node.js version we can target: nodejs/node@61b4d60

[Gasol]

This feature is very useful when deal with large stdin stream, The Async Iterator is experimental and available since Node 10 in nodejs/node#17755, and also mark as stable on Node 12.

[Richienb]

Node 10 is now in LTS. Time to implement!