garage on Python 3.10

[glisca]

Hello everyone,

I would like to run garage on Python 3.10, and of course prepare a pull request if something like this is of interest. Therefore, could you please give me some pointers towards:

1. if this makes sens at all
2. some sort of checklist, which, once fulfilled, will confirm that garage is ready to run on Python 3.10

Cheers,