Spring 4.0 support

[hauner]

https://github.com/spring-projects/spring-framework/wiki/Spring-Framework-7.0-Release-Notes

The interesting part seems to be

https://docs.spring.io/spring-framework/reference/7.0-SNAPSHOT/web/webmvc/mvc-controller/ann-requestmapping.html#mvc-ann-requestmapping-version

The question is how to provide the possible versions, OpenAPI does not support that (yet...)

OAI/OpenAPI-Specification#4212
OAI/sig-moonwalk#82