use pydantic v2

[technillogue]

[mattt]

My understanding is that this will cause incompatibilities with anyone using Pydantic 1, which I reckon is many if not most models.

Any objections to porting this to use the same "try import v2 shim for v1, fallback to actual v1" approach taken by #1622?

[technillogue]

yeah that's sensible, this is just to unblock testing

[technillogue]

wait so is there some benefit to doing this over #1622 ?