v0.3.0

Updates library dependencies to AWS SDK v2 and AWS KCL v2
Updates Scrooge to 21.1.0 from 19.3.0
Add build for Scala 2.13
Remove support for Scala 2.11, as Scrooge has dropped support for that
Update content API data models
Support new EventPayload.DeletedContent event. This introduces a new contentDelete method in the client's processor that must be implemented