Add Workflow Compensation support

[ricardozanini]

Related to: serverlessworkflow/specification#192

We need to update the parsing methods to reflect this new feature from the spec side.

[tsurdilo]

serverlessworkflow/specification#194 also changes the schema

[ricardozanini]

As soon as we merge these PRs, I'll update here. Thanks, @tsurdilo !

[ricardozanini]

Fixed in #26