Merge pull request #2423 from nextcloud/renovate/kotlin-monorepo

fix(deps): update dependency org.jetbrains.kotlin:kotlin-gradle-plugin to v2.0.21

build.gradle

@@ -13,7 +13,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 buildscript {
     ext {
-        kotlinVersion = '2.0.20'
+        kotlinVersion = '2.0.21'
         commonsVersion = '2.3.1'
     }
     repositories {