[REQ] kotlin multiplatform - support newer kotlin version

Created by: shadowsheep1

Currently library versions are

• Platform: Kotlin multiplatform.
• Kotlin version: 1.3.50
• HTTP client: Ktor 1.2.4.
• JSON processing: Kotlinx Serialization: 0.12.0.

It should be nice to address those library versions:

• Platform: Kotlin multiplatform.
• Kotlin version: 1.3.61
• HTTP client: Ktor 1.3.2.
• JSON processing: Kotlinx Serialization: 0.20.0.