Bump org.jetbrains.kotlin.android from 2.1.20 to 2.1.21

Bumps [org.jetbrains.kotlin.android](https://github.com/JetBrains/kotlin) from 2.1.20 to 2.1.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.1.20...v2.1.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin.android
  dependency-version: 2.1.21
  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

@@ -5,7 +5,7 @@ versionName = "2.6.1"
 
 #plugins versions
 agp = "8.6.1"
-kotlin = "2.1.20"
+kotlin = "2.1.21"
 dokka = "2.0.0"
 
 #dependencies versions