v0.13-RC2

This updates our dependencies to the latest general versions, and includes the changes from 0.13-RC1

Most notably, this removes the ability to convert fs2 Pure streams and pipes to akka-streams, as it relies on unsound manipulations - see the release notes for fs2 2.4.0

⚠️ Known issue: #79 Akka Sink -> fs2.Pipe implicit dsl is broken.