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/master/ChangeLog.md)
- [Commits](https://github.com/JetBrains/kotlin/commits)

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

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

build.gradle

@@ -1,6 +1,6 @@
 plugins {
     id "com.github.johnrengelman.shadow" version "8.1.1" // Import Shadow utility to package all libraries into the plugin's .jar file.
-    id "org.jetbrains.kotlin.jvm" version "2.0.20"
+    id "org.jetbrains.kotlin.jvm" version "2.0.21"
 }
 
 group = "nl.skbotnl.rewindfixog" // Declare bundle identifier.