Python 3.10 support

[rkashapov]

Hello!

It would be great to get python 3.10 supported by this excellent package.

Thanks,
Rustam

[tswast]

Thanks for the request! We're working on making sure our test infrastructure and dependencies support Python 3.10 first.

[tswast]

Now that pandas (https://pypi.org/project/pandas/1.3.4/#files) and pyarrow (https://pypi.org/project/pyarrow/6.0.0/#files) have made releases that support Python 3.10, I believe this is unblocked.

[tswast]

Looks like we're missing a geopandas dependency named fiona, but since that's very much an optional dependency, we should be able to support Python 3.10 with some adjustments to our tests to omit geopandas.