v2.2.1

This release fixes two regressions introduced by v2.2.0.

Improvements:

• New documentation chapter about GRPC API in Centrifugo.

Fixes:

• Fix client disconnect in channels with enabled history but disabled recovery
• Fix wrong Push type sent in Redis engine: Leave message was used where Join required

Docker images

• docker pull centrifugo/centrifugo:v2.2.1
• docker pull centrifugo/centrifugo:v2
• docker pull centrifugo/centrifugo:v2.2
• docker pull centrifugo/centrifugo:latest