Bump Kotlin version
Bump Kotlin version

Summary: No big changes affecting us: https://blog.jetbrains.com/kotlin/2017/11/kotlin-1-1-60-is-out/

Reviewed By: IanChilds

Differential Revision: D6334951

fbshipit-source-id: 5c3fe0380238b9ac71d854144140d186908eaf72

facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho