Change zio.json.ast.Json from sealed abstract class to sealed trait

[987Nabil]

There is no benefit, in having here an abstract class instead of a trait, as far as I can tell.
But for derivation in the zio-ecosystem, typically abstract class is not supported (zio-schema for example).
That's why I propose to change to sealed trait. The behaviour should not change at all in my opinion.

[guizmaii]

IIRC, there's a bin compat issue with sealed trait. IIRC, @fommil knows that very well as it's in his book?

[fsvehla]

Yes, I think it would be an issue; we’d need to push 0.7

[fommil]

shouldn't the bug report be with other projects, that didn't consider this well-known pattern? This is like complaining that you want coke to change the shape of their bottle because it doesn't fit in your mini-fridge.

[987Nabil]

I found another/better solution for this. I realised that deriving the schema won't work anyway. I'll add a custom schema to the json module of zio-schema.