CI: Xfails on Python 3.10

[lithomas1]

• closes #xxxx
• tests added / passed
• Ensure all linting tests pass, see here for how to run them
• whatsnew entry

The Python 3.10 CI is actually red, but the continue-on-error flag makes it so that the job is not failed. WIP because tests actually have to be fixed.
Added Xfails for some tests. Pretty much green except for #41935

[jreback]

right this was done on purpose so that we have time to fix the tests

so happy to merge this once all green otherwise

[lithomas1]

@jreback I think we should xfail these instead of doing this for now, and look into fixing them. The current setup means that its hard to tell if something breaks more tests on Python 3.10 in addition to the ones currently failing.

[jreback]

@jreback I think we should xfail these instead of doing this for now, and look into fixing them. The current setup means that its hard to tell if something breaks more tests on Python 3.10 in addition to the ones currently failing.

sure happy to do that as well. I agree that's better.

[jreback]

looks good ;
comment and ping when green

[pep8speaks]

Hello @lithomas1! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2021-06-28 15:35:29 UTC

[lithomas1]

Still WIP becaue there's a ton of flaky tests and idk what's wrong with sparse tests.

[jreback]

thanks @lithomas1 very nice!

[jreback]

@meeseeksdev backport 1.3.x

[lumberbot-app]

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