https://github.com/sendbird/sendbird-calls-ios/releases/tag/1.6.0
• Sendbird Calls now supports making group calls in a room.
• Added Room.
• Added createRoom(with:completionHandler:) in SendBirdCall.
• Added fetchRoom(by:completionHandler:) in SendBirdCall.
• Added getCachedRoom(by:completionHandler:) in SendBirdCall.
• Added RoomType.
• Added RoomParams.
• Added State in Room.
• Added EnterParams in Room.
• Added RoomDelegate.
• Added Participant, LocalParticipant and RemoteParticipant.
• Added Participant.State.
• Improved stability.
