Merge pull request #3158 from nextcloud/renovate/kotlin-monorepo

fix(deps): update dependency org.jetbrains.kotlin:kotlin-gradle-plugin to v2.3.21

Author: nextcloud-android-bot

build.gradle

@@ -10,7 +10,7 @@
 
 buildscript {
     ext {
-        kotlinVersion = '2.3.20'
+        kotlinVersion = '2.3.21'
         commonsVersion = '2.4.1'
 		androidCommonsVersion = '1.1.1'
         nextcloudAndroidCommonLib = "0.33.2"