Bump jvm from 1.6.10 to 1.8.21 in /lib/kotlin (#2803)

Bumps [jvm](https://github.com/JetBrains/kotlin) from 1.6.10 to 1.8.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](https://github.com/JetBrains/kotlin/compare/v1.6.10...v1.8.21)

---
updated-dependencies:
- dependency-name: jvm
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/lib/kotlin/settings.gradle.kts b/lib/kotlin/settings.gradle.kts
index c252add..99ceaf0 100644
--- a/lib/kotlin/settings.gradle.kts
+++ b/lib/kotlin/settings.gradle.kts
@@ -18,7 +18,7 @@
  */
 pluginManagement {
     plugins {
-        kotlin("jvm") version "1.6.10"
+        kotlin("jvm") version "1.8.21"
         id("com.ncorti.ktfmt.gradle") version "0.8.0"
     }
 }