Update kotlin monorepo to v2.1.21 (#263)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build.gradle

@@ -2,7 +2,7 @@ import org.gradle.api.internal.classpath.ModuleRegistry
 import org.gradle.api.internal.project.ProjectInternal
 
 buildscript {
-  ext.kotlinVersion = '2.1.10'
+  ext.kotlinVersion = '2.1.21'
 
   repositories {
     mavenCentral()