Upgrade to ZIO 2

[alexvanolst]

ZIO is at RC-1 now https://github.com/zio/zio/releases/tag/v2.0.0-RC1

There exists a ScalaFix rule that will cover the bulk of the simple API changes:
https://github.com/zio/zio/blob/series/2.x/scalafix/rules/src/main/scala/fix/Zio2Upgrade.scala
We highly recommend starting with that, and then working through any remaining compilation errors :)

To assist with the rest of the migration, we have created this guide:
https://zio.dev/next/howto/migrate/zio-2.x-migration-guide/

[alexvanolst]

I've started working on this here: https://github.com/alexvanolst/zio-entity/tree/zio2

Currently blocked waiting for a release of zio-interop-cats for cats 2.x. Once there is a release with zio/interop-cats#475 merged I will pick up on this again