Add support for JDK 11

[jcustenborder]

[timonmat]

@jcustenborder I was trying to use the XML transforms with Confluent Docker images, which are all JDK 11 since 6.0, and was met with errors. rebuilding seems to require a bit more work than just adding #28 PR as well, because of Maven pushing error after error with dependencies etc, and fixing one leading to another.

So it seems the plugin, and the confluent hub version of it basically hasn't worked for a long time with Confluent's official cp-all docker-compose way of setting up dev and test environments.

So my question is really that is this plugin abandoned and forgotten, or is there a chance of getting an official functional build to confluent hub at some point in the near future? It's been a year since the last build anyway. It would be sad to see it depricated, as it does seem like the fastest way from xml and xsd to kafka data with a schema and proper field types.. ...I guess, as I can't test to verify.

[selamanse]

@jcustenborder @timonmat I managed to get it working with current confluent 7.0.1 docker images. My version is here and here

I had to point the build to github packages (done with gh actions), but still based on your parental structure @jcustenborder. I'd like to contribute these changes so this working version could show up in confluent hub for others too.

The baseline change (start) for this is here. Could anyone of the contributors please have a look?