Bump org.jetbrains.kotlin:kotlin-stdlib from 2.0.20 to 2.0.21 (#62)

Bumps [org.jetbrains.kotlin:kotlin-stdlib](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:kotlin-stdlib
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle.kts

@@ -4,7 +4,7 @@ group = "io.github.mikaojk"
 version = "1.0.0"
 
 val junitJupiterVersion = "5.11.2"
-val kotlinVersion = "2.0.20"
+val kotlinVersion = "2.0.21"
 val ktfmtVersion = "0.44"
 val javaVersion = JavaVersion.VERSION_21