v1.0.0-alpha2.12

What's changed

• Added a new Metadata property to both WorkflowDefinition and TaskDefinition, addressing serverlessworkflow/specification#996
• Added a Certificate, Digest and OIDC authentication schemes, and updated the OAuth2AuthenticationSchemeDefinition, addressing serverlessworkflow/specification#973
• Added fluent builders for the newly added authentications
• Added services to fluently validate the DSL
• Added referenceable timeouts and retries, thus addressing serverlessworkflow/specification#1002
• Added validation unit tests

Full Changelog: v1.0.0-alpha2.11...v1.0.0-alpha2.12