Support for Scala 2.13

[sven-lehmann]

Hey!
We would like to use this Kinesis Connector in a project that uses Scala 2.13. As I can see there is currently no 2.13 build for this project. When trying to manually build the project, I'm facing the same error message as reported in #7 .

error: scala.reflect.internal.FatalError:
  bad constant pool index: 0 at pos: 48445
     while compiling: <no file>
        during phase: globalPhase=<no phase>, enteringPhase=<some phase>
     library version: version 2.13.8
    compiler version: version 2.13.8

Maybe it is possible to make a 2.13 version available as well, either on Maven Central or on S3.
Thanks!