Update plugin org.springframework.boot to v3.4.3

Author: renovate[bot]

build.gradle

@@ -1,5 +1,5 @@
 plugins { 
-    id "org.springframework.boot" version "3.3.6"
+    id "org.springframework.boot" version "3.4.3"
     id "io.spring.dependency-management" version "1.1.6" 
     id "io.freefair.lombok" version "8.11"
     id "io.freefair.maven-publish-java" version "8.11"