Update plugin org.springframework.boot to v4

Author: renovate[bot]

build.gradle.kts

@@ -6,7 +6,7 @@ import org.springframework.boot.gradle.tasks.bundling.BootJar
 val currentYear = 2024
 
 plugins {
-    id("org.springframework.boot") version "3.5.9" apply false
+    id("org.springframework.boot") version "4.0.3" apply false
     kotlin("jvm") version "2.3.0" apply false
     kotlin("plugin.spring") version "2.3.0" apply false