Migrating from 2.x to 3.0

1. Update to the latest 2.x version of Funcky (2.7.1) and fix all warnings.
2. Update to Funcky 3.0.
3. Run dotnet format analyzers. This will migrate Option<T>.None() to Option<T>.None for you.
   This command sometimes fails while loading your project(s). --no-restore might help with that.
4. Build and fix other compilation failures.
5. You might need to re-run dotnet format analyzers after fixing other errors.
6. Important: Check if you're using System.Text.Json to serialize Options. This will no longer work automatically. You need to add the OptionJsonConverter yourself.