Update to spring-boot-starter 3, requiring Java 17

[cuddihyge]

After Nov 23 springboot 2.7 isn't supported officially (still open source).
Dependabot wants semtk to use the parent: spring-boot-starter-parent 3.1.2.
This requires java 17.
Lebanon servers and my/jenny environments are still java 11.

https://spring.io/blog/2022/05/24/preparing-for-spring-boot-3-0