Support generating kotlin.time.Duration

[this-is-spear]

Summary

Issue : #721

Added because Kotlin doesn't support generating duration objects.

How Has This Been Tested?

• Verify that creates a duration object
• Verify that generates an object with a duration variable

Is the Document updated?

There's not enough content to update to documentation.

[seongahjo]

Can you add documentation that the Kotlin Duration type is supported as of 1.0.15 in the release note?

[this-is-spear]

I've added it to the release notes, thank you 😊