[project] bump pydantic (#94)

Why
===
* I was trying to start using uv in ai-infra and it requires a
--prerelease=allow flag to be passed to install prereleases.
* We most likely don't need a prerelease here anymore, now that there is
a later version available

What changed
===
* Set pyproject.toml pydantic to use the latest version
* `poetry lock --no-update`

Test plan
===
* `poetry install` worked
* CI passes