Update kotlin monorepo to v2.4.20

Author: renovate[bot]

gradle/libs.versions.toml

@@ -1,6 +1,6 @@
 [versions]
 
-kotlin = "2.4.10" # must match Gradle's embedded Kotlin version https://docs.gradle.org/current/userguide/compatibility.html#kotlin
+kotlin = "2.4.20" # must match Gradle's embedded Kotlin version https://docs.gradle.org/current/userguide/compatibility.html#kotlin
 kotlin-dokka = "1.9.20"
 kotlinx-serialization = "1.11.0"