Bump org.springframework.boot from 2.7.18 to 3.4.2

Bumps [org.springframework.boot](https://github.com/spring-projects/spring-boot) from 2.7.18 to 3.4.2.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.7.18...v3.4.2)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

build.gradle

@@ -5,7 +5,7 @@ plugins {
   id 'java'
   id "io.freefair.lombok" version "8.12.1"
   id 'io.spring.dependency-management' version '1.1.7'
-  id 'org.springframework.boot' version '2.7.18'
+  id 'org.springframework.boot' version '3.4.2'
   id 'com.github.kt3k.coveralls' version '2.12.2'
   id 'hmcts.ccd.sdk' version '5.5.16'
   id 'com.github.ben-manes.versions' version '0.51.0'