Official 1.1 update

This 1.1 release brings many new features from 1.0:

• Transient publishing supported on channels
• Push notifications are now generally available
• Experimental support for batch REST publishing
• Access to the Ably DSX

See the complete release notes at https://blog.ably.io/ablys-client-library-sdks-1-1-release-8165c73c76fd