Update plugin org.springframework.boot to v3.4.2

Author: renovate[bot]

build.gradle

@@ -1,6 +1,6 @@
 plugins {
 	id 'java'
-	id 'org.springframework.boot' version '3.3.5'
+	id 'org.springframework.boot' version '3.4.2'
 	id 'io.spring.dependency-management' version '1.1.7'
 	id 'org.eclipse.jkube.kubernetes' version '1.15.0'
 	id 'com.palantir.git-version' version '3.1.0'