Update plugin org.jetbrains.kotlin.plugin.serialization to v1.9.21

Author: renovate[bot]

build.gradle.kts

@@ -4,7 +4,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 plugins {
     // Apply the Kotlin JVM plugin to add support for Kotlin.
     id("org.jetbrains.kotlin.jvm") version "1.7.22"
-    kotlin("plugin.serialization") version "1.7.22"
+    kotlin("plugin.serialization") version "1.9.21"
     id("com.github.johnrengelman.shadow") version "7.1.2"
 	id("io.gitlab.arturbosch.detekt") version "1.22.0"