Update plugin org.springframework.boot to v3.5.4 (#294)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build.gradle

@@ -5,7 +5,7 @@ plugins {
   id 'java'
   id "io.freefair.lombok" version "8.14"
   id 'io.spring.dependency-management' version '1.1.7'
-  id 'org.springframework.boot' version '3.5.3'
+  id 'org.springframework.boot' version '3.5.4'
   id 'com.github.kt3k.coveralls' version '2.12.2'
   id 'hmcts.ccd.sdk' version '5.6.0'
   id 'com.github.ben-manes.versions' version '0.51.0'