Bump org.jetbrains.kotlin:kotlin-gradle-plugin from 1.9.20 to 1.9.21

Bumps [org.jetbrains.kotlin:kotlin-gradle-plugin](https://github.com/JetBrains/kotlin) from 1.9.20 to 1.9.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.9.20...v1.9.21)

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

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -69,7 +69,7 @@ org-hamcrest = "org.hamcrest:hamcrest:2.2"
 org-hibernate-orm-hibernate-core = "org.hibernate.orm:hibernate-core:6.3.2.Final"
 org-hsqldb = "org.hsqldb:hsqldb:2.7.2"
 org-jetbrains-kotlin-kotlin-bom = { module = "org.jetbrains.kotlin:kotlin-bom", version.ref = "org-jetbrains-kotlin" }
-org-jetbrains-kotlin-kotlin-gradle-plugin = "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.20"
+org-jetbrains-kotlin-kotlin-gradle-plugin = "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.21"
 org-jetbrains-kotlinx-kotlinx-coroutines-bom = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-bom", version.ref = "org-jetbrains-kotlinx" }
 org-junit-junit-bom = "org.junit:junit-bom:5.10.1"
 org-mockito-mockito-bom = { module = "org.mockito:mockito-bom", version.ref = "org-mockito" }