Gradle projects with Kotlin scripts complain about bundled Kotlin runtime

The Gradle `compileKotlin` task complains about the bundled into the Spine Bootstrap plugin Kotlin runtime:

```
.gradle\caches\modules-2\files-2.1\io.spine.tools\spine-bootstrap\1.5.17\422a13802c7faafa2fc4e5c07858ea39a1cb9b39\spine-bootstrap-1.5.17.jar: Library has Kotlin runtime bundled into it
```

