build(deps): bump plugin.serialization from 2.0.20 to 2.0.21 (#17)

Bumps [plugin.serialization](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: plugin.serialization
  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>

buildSrc/build.gradle.kts

@@ -1,6 +1,6 @@
 plugins {
     kotlin("jvm") version "2.0.20"
-    kotlin("plugin.serialization") version "2.0.20"
+    kotlin("plugin.serialization") version "2.0.21"
 
 }