v5.0.0

In this release we adapt phpcent for Centrifugo v4:

• generatePrivateChannelToken renamed to generateSubscriptionToken and now supports providing sub (user ID) claim - according to channel auth docs and v4 subscription token migration docs.
• In generateConnectionToken method $userId argument is not optional anymore – it should be explicitly provided. You can still pass empty string explicitly for anonymous users.

Please note, that you can generate Centrifugo tokens using any JWT library for PHP.