[4.0.0] ProduceEvent.getData returns String rather than Object

[fjtirado]

What happened:
The serverless workflow specification (version 0.8) specified that ProducedEvent.data should be an string or object, but the generated POJO returns string

What you expected to happen:
That the generated POJO returns Object

How to reproduce it:

Anything else we need to know?:

Environment:

• Specification version used: