v0.6.0

This release contains support for postage channels, as well as several breaking changes.

Changes:

• Add support for postage channels.
• Remove the barrier and subscription channel implementations. See the readme for migration docs.
• Remove the LifelineSender and LifelineReceiver wrappers, so that channel endpoints which implement Sink or Stream can be used when retrieved from the bus.
• In the prelude, remove the export of Sender and Receiver. This allows the use of the prelude in programs that import Sink or Stream from postage, tokio-stream, or the upcoming std Stream.
• Update to async-std v1.9

Upgrading:

• If you need Stream/Sink combinators, take a look at postage, or tokio-stream.
• The barrier channel can be replaced with postage::barrier.
• The subscription channel code can be found here.