chore(deps): update plugin spring-boot to v4

Author: renovate[bot]

gradle/libs.versions.toml

@@ -9,5 +9,5 @@ indra-git = { id = "net.kyori.indra.git", version.ref = "indra" }
 jib = { id = "com.google.cloud.tools.jib", version = "3.5.2" }
 sentry = { id = "io.sentry.jvm.gradle", version = "5.12.2" }
 spotless = { id = "com.diffplug.spotless", version = "7.2.1" }
-spring-boot = { id = "org.springframework.boot", version = "3.5.9" }
+spring-boot = { id = "org.springframework.boot", version = "4.0.1" }
 spring-deps = { id = "io.spring.dependency-management", version = "1.1.7" }