Bump org.jetbrains.kotlin.jvm from 2.0.20 to 2.0.21

Bumps [org.jetbrains.kotlin.jvm](https://github.com/JetBrains/kotlin) from 2.0.20 to 2.0.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v2.0.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.20...v2.0.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin.jvm
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -2,7 +2,7 @@ buildscript {
     repositories {
         mavenCentral()
     }
-    ext.kotlin_version = '2.0.20'
+    ext.kotlin_version = '2.0.21'
 
     ext.versions = [
             junit: '5.9.1',