Bump the kotlin group with 6 updates (#464)

Bumps the kotlin group with 6 updates:

| Package | From | To |
| --- | --- | --- |
| [org.jetbrains.kotlin:kotlin-stdlib-jdk8](https://github.com/JetBrains/kotlin) | `2.1.20` | `2.1.21` |
| [org.jetbrains.kotlin:kotlin-reflect](https://github.com/JetBrains/kotlin) | `2.1.20` | `2.1.21` |
| [org.jetbrains.kotlin.android](https://github.com/JetBrains/kotlin) | `2.1.20` | `2.1.21` |
| [org.jetbrains.kotlin.multiplatform](https://github.com/JetBrains/kotlin) | `2.1.20` | `2.1.21` |
| [org.jetbrains.kotlin.plugin.serialization](https://github.com/JetBrains/kotlin) | `2.1.20` | `2.1.21` |
| [org.jetbrains.kotlin.plugin.compose](https://github.com/JetBrains/kotlin) | `2.1.20` | `2.1.21` |


Updates `org.jetbrains.kotlin:kotlin-stdlib-jdk8` 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)

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

Updates `org.jetbrains.kotlin.android` 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)

Updates `org.jetbrains.kotlin.multiplatform` 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)

Updates `org.jetbrains.kotlin.plugin.serialization` 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)

Updates `org.jetbrains.kotlin.plugin.compose` 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)

Updates `org.jetbrains.kotlin:kotlin-reflect` 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:kotlin-stdlib-jdk8
  dependency-version: 2.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin:kotlin-reflect
  dependency-version: 2.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin.android
  dependency-version: 2.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin.multiplatform
  dependency-version: 2.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin.plugin.serialization
  dependency-version: 2.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin.plugin.compose
  dependency-version: 2.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kotlin
- dependency-name: org.jetbrains.kotlin:kotlin-reflect
  dependency-version: 2.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: kotlin
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ agp = "8.10.0"
 coroutines = "1.10.2"
 hilt = "2.56.2"
 hiltExtensions = "1.2.0"
-kotlin = "2.1.20"
+kotlin = "2.1.21"
 ktor = "3.1.3"
 activity = "1.10.1"
 lifecycle = "2.9.0"