fix(deps): bump org.jetbrains.kotlin.jvm from 2.0.20 to 2.0.21

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

Signed-off-by: dependabot[bot] <[email protected]>

build.gradle.kts

@@ -5,7 +5,7 @@ group = "tech.relaycorp"
 
 plugins {
     // Apply the Kotlin JVM plugin to add support for Kotlin.
-    id("org.jetbrains.kotlin.jvm") version "2.0.20"
+    id("org.jetbrains.kotlin.jvm") version "2.0.21"
 
     // Apply the java-library plugin for API and implementation separation.
     `java-library`