[REQ] Feature Request Description

[MEJIOMAH17]

Is your feature request related to a problem? Please describe.

Kotlinx-serialization generator use KSerializable in enum. KSerializable does not exist in stable version of https://github.com/Kotlin/kotlinx.serialization

Describe the solution you'd like

Replace KSerializable to Serializable

[AlexTrotsenko]

Looks like old "pre-stable" version is used currently.

Or at least it is what documented in the Kotlin generators documentation:
https://github.com/OpenAPITools/openapi-generator/blob/master/docs/generators/kotlin.md

Seems like there is PR to update it to the stable version, but it's still open for 2 months already:
#9232