default Kotlin Version
The default version of the Kotlin
gradle plugin. Use the kotlinVersion (or Project.kotlinVersion) method to specify a specific kotlin plugin version.
NOTE. Future versions of MetaBuild will change the default values. So if you care about the version please specify it explicitly.
Project.kotlin and Project.kotlinMultiPlatform look for a Kotlin aspect. If none are found, then this default value is used. The kotlin version is also used by Kotlin.kotlinReflect.