Downgrade FastAPI

[ebr]

FastAPI is broken on main (17d8bbf) - any request returns a 500 type error.

This PR downgrades fastapi and related packages again. I wish I had a better solution, but this at least fixes the immediate breakage.

Fixes #3038

[psychedelicious]

On Linux, I also need to revert to an earlier fastapi version. I haven't attempted to bisect the version to identify the latest that still works, so I've also just rolled back to 0.85.0 as it works fine.

[Kyle0654]

Do you mind finding which version is broken and on what platform and why? These versions together are all working for me, and I stepped them all back from latest until I had a working combination. I feel like there's something from FastAPI that I actually needed to upgrade for too (though I can't remember what... Possibly related to schemas).

[Kyle0654]

Put another way, could you find the latest version of FastAPI that does work?

[ebr]

@Kyle0654 I stepped through versions, and the latest one that does work is 0.88.0. I updated the PR accordingly. Didn't need to downgrade uvicorn actually either.

As for "why" - I spent some time on this, but couldn't figure out the root cause. interestingly, the KeyError in the stack trace references different Invocation types seemingly at random.

[lstein]

Lgtm