Version 0.8.0-rc01

[dkhalanskyjb]

Notes:

• This release is behind schedule on kotlinx.datetime.Instant removal: https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/instant.md#description-of-the-process According to the plan, 0.8.0 is supposed to advance the deprecation level on kotlinx.datetime.Instant in the compatibility artifact to ERROR. However, despite the major version bump (necessary due to a breaking change being included), 0.8.0 is actually quite a minor release, mostly consisting of small convenience API additions. It makes sense to try reducing the friction of upgrading to it. 0.9.x will include more significant breaking changes and require upgrading to a new Kotlin version, one where kotlin.time.Instant is stable—promoting the deprecation to ERROR there feels to me like a good fit.
• The version scheme is new. Previously, we had RC1 or RC.1, but as part of a Kotlin-wide effort for unified versioning, this is rc01 now, even though it's inconsistent with our earlier choices. kotlinx.coroutines already published such a release: https://github.com/Kotlin/kotlinx.coroutines/releases/tag/1.11.0-rc01