Please support V2 of wire channel wire protocol (introduced in Phoenix 1.3)

[axelson]

One of the new features in Phoenix 1.3 is "[Channel] Add V2 of wire channel wire protocol with resolved race conditions and compacted payloads"

https://github.com/phoenixframework/phoenix/blob/master/CHANGELOG.md

It would be great to have support for the V2 protocol in JavaPhoenixChannels.