chore(deps): update plugin org.jetbrains.kotlin.jvm to v2.1.21 (#172)

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

Author: renovate[bot]

build.gradle.kts

@@ -4,7 +4,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
     id("org.springframework.boot") version "3.4.0"
-    kotlin("jvm") version "2.1.20"
+    kotlin("jvm") version "2.1.21"
     kotlin("plugin.spring") version "2.1.20"
 
     // graphql plugins