MicroProfile® OpenAPI 4.2

This is a minor release, to include:

• deprecation of allowEmptyValue on @Header for future removal
• support for creating a multipleOf schema assertion from a @Digits annotation
• clarify how setExtension and getExtension work with schema properties
• addition of example and examples to @Header
• TCK bug fixes
• Clarification of use of @ExternalDocumentation on types

Issues planned for this release are listed under the 4.2 milestone.