Bump kotlin-serialization from 1.7.20 to 1.7.21

Bumps [kotlin-serialization](https://github.com/JetBrains/kotlin) from 1.7.20 to 1.7.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](https://github.com/JetBrains/kotlin/commits)

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

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -4,7 +4,7 @@ buildscript {
 	}
 	dependencies {
 		classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.7.21'
-		classpath 'org.jetbrains.kotlin:kotlin-serialization:1.7.20'
+		classpath 'org.jetbrains.kotlin:kotlin-serialization:1.7.21'
 	}
 }