Upgrade kotlinx-datetime to 0.7.1

[ecstatic-morse]

This involves migrating to the builtin versions of a few types:

• kotlinx.datetime.Instant -> kotlin.time.Instant
• kotlinx.datetime.Clock -> kotlin.time.Clock

These are still experimental, so add the corresponding optIn flag as well.

[simolus3]

Thanks!

[simolus3]

Actually it looks like we'll have a hard time with this:

1. Versions of the supabase-kt project older than 3.2.1 don't support the datetime migration yet (there are runtime failures about missing classes - java.lang.ClassNotFoundException: kotlinx.datetime.serializers.InstantIso8601Serializer).
2. For me, updating supabase-kt to 3.2.1 resulted in compiler errors, probably because we need to upgrade our Kotlin version too.
3. However, we're currently blocked on updating Kotlin due to SKIE 0.10.4 and Kotlin 2.2.0 can't create macOS frameworks touchlab/SKIE#162

Is this blocking something for you?

[ecstatic-morse]

Not a blocker. This was just the last of my dependencies using version 0.6.x of kotlinx-datetime.

I mistakenly thought this only required kotlin >2.1.20 and kotlinx-serialization >1.9.0, but it looks like there's a bit more going on.

Feel free to put this on the pause until things settle down a bit.