Bump kotlin from 2.2.20 to 2.2.21

Bumps `kotlin` from 2.2.20 to 2.2.21.

Updates `org.jetbrains.kotlin:kotlin-stdlib` from 2.2.20 to 2.2.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.2.20...v2.2.21)

Updates `org.jetbrains.kotlin:kotlin-test-junit5` from 2.2.20 to 2.2.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.2.20...v2.2.21)

Updates `org.jetbrains.kotlin:kotlin-gradle-plugin` from 2.2.20 to 2.2.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.2.20...v2.2.21)

Updates `org.jetbrains.kotlin:kotlin-power-assert` from 2.2.20 to 2.2.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.2.20...v2.2.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib
  dependency-version: 2.2.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-test-junit5
  dependency-version: 2.2.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-gradle-plugin
  dependency-version: 2.2.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-power-assert
  dependency-version: 2.2.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ apiguardian = "1.1.2"
 junit-jupiter = "6.0.0"
 junit-platform = "6.0.0"
 assertJ = '3.27.6'
-kotlin = '2.2.20'
+kotlin = '2.2.21'
 #opentest4j = '1.3.0'
 #archunit = '1.3.0'
 #mockito = '5.14.2'