v0.4.0

Changes from 0.3.2:

• Fix a type inference issue in Producer.make (#58) by @svroonland
• Add Serializer and Deserializer constructors for wrapping their Kafka equivalents (#60) by @svroonland
• Implement graceful shutdown (#55) by @adamgfraser
• Add a wrapper for Kafka's AdminClient (#77) by @TimPigden
• Update to ZIO 1.0.0-RC17 (#76) by @svroonland

In ZIO 1.0.0-RC17, ZStream#aggregate was renamed to aggregateAsync to better reflect its nature. In its place is a synchronous method that does the same thing. Be sure to update your code!