Fix evaluating stringified annotations in Python 3.10

[chaen]

I've bumped into the exact same issue as tiangolo/typer#598 so I solved it like tiangolo/typer#721 😄

I'll try to add tests soon but if you can do it faster, please feel free !!

[chaen]

So frankly, I am not sure which one of the multiple options my issue is, maybe even a mixture of all of that:

• Import of __future__ annotations breaks class dependency with NameError #9085
• A bit more explanation about "forward_refs" and how to use it. pydantic/pydantic#4521
• An error about annotations in __future__ annotations #6465

So I am not even sure that this fix is correct, but it definitely fixes my issues.
I took the tests reported in 2 of the issues, added them as unit tests, and it fixes it. But again, I am not completely sure this is correct :-)

[chaen]

hi @tiangolo I checked the #10370 roadmap but it isn't entirely clear to me the timescale we are talking about for that PR or all those marked p2 ? Let me know if there's anything I still need to do here :-)