Use readable-stream 3

[realityking]

This will require a new major release.

[jimmywarting]

i would have wished it used the builtin node version so you would always get the latest version... otherwise this can lag behind in new features such as not being able to use async iterator... readable-stream is already lagging behind and installs unnecessary dependencies

if you are gona make a breaking release, then also take the opportunity to use class extend instead of using the discuraged inherits fn