Bump spring-security-bom from 5.5.3 to 5.6.0

Bumps [spring-security-bom](https://github.com/spring-projects/spring-security) from 5.5.3 to 5.6.0.
- [Release notes](https://github.com/spring-projects/spring-security/releases)
- [Changelog](https://github.com/spring-projects/spring-security/blob/main/RELEASE.adoc)
- [Commits](spring-projects/spring-security@5.5.3...5.6.0)

---
updated-dependencies:
- dependency-name: org.springframework.security:spring-security-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

build.gradle

@@ -198,7 +198,7 @@ configure(allJavaProjects) {
     }
 
     def webauthn4jVersion = '0.18.0.RELEASE'
-    def springSecurityVersion = '5.5.3'
+    def springSecurityVersion = '5.6.0'
     def springBootVersion = '2.3.1.RELEASE'
     def hibernateValidatorVersion = '6.2.0.Final'
     def thymeleafVersion = '3.0.4.RELEASE'