build(deps): bump org.springframework.boot from 2.5.5 to 2.5.6

Bumps [org.springframework.boot](https://github.com/spring-projects/spring-boot) from 2.5.5 to 2.5.6.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.5.5...v2.5.6)

---
updated-dependencies:
- dependency-name: org.springframework.boot
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

build.gradle

@@ -5,7 +5,7 @@ plugins {
     id 'org.sonarqube' version '3.3'
     id 'io.freefair.lombok' version '6.2.0'
     id 'fr.brouillard.oss.gradle.jgitver' version '0.9.1'
-    id 'org.springframework.boot' version '2.5.5'
+    id 'org.springframework.boot' version '2.5.6'
     id 'io.spring.dependency-management' version '1.0.11.RELEASE'
 }