Protocol Buffer client needs e2e test support #4382

Similar to https://github.com/kubernetes-client/java/blob/master/e2e/src/test/java/io/kubernetes/client/e2e/basic/CoreV1ApiTest.java we should add a test which uses protocol buffers for transport.

There is an example of how to use protocol buffers here:
https://github.com/kubernetes-client/java/blob/master/examples/examples-release-latest/src/main/java/io/kubernetes/client/examples/ProtoExample.java