Enable Pydantic v1/v2 dual-compatibility

[mattwthompson]

Description

This is my attempt at taking #736 over the finish line

Changelog description

Status

• Code base linted
• Ready to go

closes #736

[loriab]

lgtm, thanks!

[loriab]

I don't have official powers here at qcf, so merge decision/schedule is all @bennybp .

[bennybp]

Thanks! I also removed the pins in some testing environments.

I remember there being some error with pydantic-settings being a separate package. Has that changed recently? It isn't in the dependency lists but everything seems to work

[mattwthompson]

My guess is you're thinking of this issue: MolSSI/QCElemental#312

In which case it's still a problem, but under the umbrella of changes required to leverage the v2 API. Since this just allows access to v1 via v2 I think that can still be pushed into the future.

[bennybp]

Oh yes, of course :) Thanks for finishing this up!

[mattwthompson]

Thank you!