chore(deps): bump org.jetbrains.kotlin.jvm from 2.3.0 to 2.3.21

Bumps org.jetbrains.kotlin.jvm from 2.3.0 to 2.3.21.

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin.jvm
  dependency-version: 2.3.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -6,7 +6,7 @@ opentest4j = "1.3.0"
 # plugins
 changelog = "2.5.0"
 intelliJPlatform = "2.15.0"
-kotlin = "2.3.0"
+kotlin = "2.3.21"
 kover = "0.9.8"
 qodana = "2026.1.0"