SequenceNumber class is not POJO type

SequenceNumber class is currently part of the "Kinesis-Stream-Shard-State", but it does not follow requirements of POJO compatible type. Because of that we are getting warning like this:

TypeExtractor - class software.amazon.kinesis.connectors.flink.model.SequenceNumber does not contain a setter for field sequenceNumber
While the warning itself or inability to use optimal sterilizer for such a small state is not the problem, this warning prevents us to disable Generic Types via disableGenericTypes()
So, the problem is similar to https://issues.apache.org/jira/browse/FLINK-15904