Add Python 3.10

[hugovk]

Fixes #15.

Python 3.10 was released on 2021-10-04:

• https://discuss.python.org/t/python-3-10-0-is-now-available/10955

[codecov]

Codecov Report

Merging #19 (936933f) into master (5d0ae28) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master       #19   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           14        14           
  Lines          343       343           
  Branches        52        52           
=========================================
  Hits           343       343           

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[bolsote]

Thanks for the change, and apologies for my rather long delay in reviewing. I was unavailable for quite some time.

The changes look good. Semgrep seems to be as temperamental as usual, but I'll deal with that separately. Only one nitpick: would it be possible to also include a 3.10 environment in tox.ini?

[hugovk]

No need to apologise :)

There's already py310 in tox.ini's envlist, is something else needed?

[bolsote]

Oh, completely missed a whole file for review, somehow. Everything is absolutely fine, I'll just approve and merge now. Thank you very much for the contribution.

As an aside, I'm aware of what's going on in gweis/isodate#65 and I'd like to have a chat about it. My email should be in my profile, so feel free to ping me any time.