bumping the major

[mcollina]

readable-stream v3!

There are a bunch of things we want to put in there that are semver-major, one of which is cutting down the supported node versions.

When do we want to do it? Node v9, Node v10?

[calvinmetcalf]

what are the things (besides just dropping support) ?

[mcollina]

First one: nodejs/node#13065

[Croydon]

And #212 please

[mcollina]

This will happen when we will start pulling from Node 10. We have a series of major changes landing there as well.