Bump the kotlin group across 1 directory with 3 updates

Bumps the kotlin group with 3 updates in the / directory: [org.jetbrains.kotlin:kotlin-gradle-plugin](https://github.com/JetBrains/kotlin), [org.jetbrains.kotlin:kotlin-stdlib](https://github.com/JetBrains/kotlin) and [org.jetbrains.kotlin:kotlin-reflect](https://github.com/JetBrains/kotlin).


Updates `org.jetbrains.kotlin:kotlin-gradle-plugin` from 1.9.24 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@v1.9.24...v2.0.21)

Updates `org.jetbrains.kotlin:kotlin-stdlib` from 1.9.24 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@v1.9.24...v2.0.21)

Updates `org.jetbrains.kotlin:kotlin-reflect` from 1.9.24 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@v1.9.24...v2.0.21)

Updates `org.jetbrains.kotlin:kotlin-stdlib` from 1.9.24 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@v1.9.24...v2.0.21)

Updates `org.jetbrains.kotlin:kotlin-reflect` from 1.9.24 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@v1.9.24...v2.0.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-gradle-plugin
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin:kotlin-reflect
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin:kotlin-reflect
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: kotlin
...

Signed-off-by: dependabot[bot] <[email protected]>

build.gradle

@@ -2,7 +2,7 @@
 apply plugin: 'io.github.gradle-nexus.publish-plugin'
 
 buildscript {
-    ext.kotlin_version = '1.9.24'
+    ext.kotlin_version = '2.0.21'
     ext.mockito_version = '5.12.0'
     ext.androidJunit5Version = '1.4.2.1'
     ext.junitJupiterVersion = "5.4.2"