build(deps): bump spring-boot.version from 3.5.5 to 3.5.6

[paul58914080]

Checklist:

• My code follows the contribution guidelines of this project
• I have performed a self-review of my own code
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• My commits follow conventional commit message guidelines

[Copilot]

Pull Request Overview

This PR bumps the Spring Boot version property to the latest patch level to pick up fixes and improvements.

• Update spring-boot.version from 3.5.5 to 3.5.6
• No code changes; build/dependency update only