Bump org.jetbrains.kotlinx:lincheck-jvm from 2.18.1 to 2.21-IDEA-PLUGIN

Bumps [org.jetbrains.kotlinx:lincheck-jvm](https://github.com/Kotlin/kotlinx-lincheck) from 2.18.1 to 2.21-IDEA-PLUGIN.
- [Release notes](https://github.com/Kotlin/kotlinx-lincheck/releases)
- [Changelog](https://github.com/JetBrains/lincheck/blob/master/RELEASE.md)
- [Commits](https://github.com/Kotlin/kotlinx-lincheck/commits)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlinx:lincheck-jvm
  dependency-type: direct:production
...

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

gradle/libs.versions.toml

@@ -60,7 +60,7 @@ junit-testng = "1.0.4"
 junit4 = "4.13.2"
 junit5 = "5.10.0-M1"
 kotlin = "1.8.22"
-lincheck = "2.18.1"
+lincheck = "2.21-IDEA-PLUGIN"
 mockito = "5.4.0"
 nekohtml = "1.9.22"
 nexus-publish = "2.0.0-rc-1"