chore(deps): update plugin org.jetbrains.kotlin.jvm to v1.9.20

Author: renovate[bot]

build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    kotlin("jvm") version "1.9.10"
+    kotlin("jvm") version "1.9.20"
     id("net.minecrell.plugin-yml.bukkit") version "0.6.0" apply false
     id("org.jetbrains.kotlinx.kover") version "0.6.1"
     id("org.jetbrains.dokka") version "1.9.10"