chore(deps): bump kotlin.version from 2.0.20 to 2.0.21 (#255)

Bumps `kotlin.version` from 2.0.20 to 2.0.21.

Updates `org.jetbrains.kotlin:kotlin-bom` 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)

Updates `org.jetbrains.kotlin:kotlin-maven-plugin` from 2.0.20 to 2.0.21

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pom.xml

@@ -39,7 +39,7 @@
 		<maven.compiler.target>${maven.compiler.source}</maven.compiler.target>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
-		<kotlin.version>2.0.20</kotlin.version>
+		<kotlin.version>2.0.21</kotlin.version>
 		<kotlin.coroutine.version>1.9.0</kotlin.coroutine.version>
 
 		<http4k.version>5.32.4.0</http4k.version>