Backport Python 3.10 fixes

[bnavigator]

This is a backport of #13282 and #13371 (minus the AppVeyor and GHA on Windows changes).

I am using it for the openSUSE build of 7.30.1, because otherwise I can't built a package for Python 3.10.

[bnavigator]

Gna, too soon. It built on openSUSE python310 flavor. 😢

[Carreau]

Sounds reasonable. Is there anything else we can do to make your life easier ? Like add specific openSUSE build file to the repo ?

[bnavigator]

No, the openSUSE build files are maintained at the build service: https://build.opensuse.org/package/show/devel:languages:python:jupyter/python-ipython

Thanks for your work!

[Carreau]

Thank you for packaging on openSUSE.

If there is anything i can carry upstream, or step I co so at release to make your life easier let me know.

Note that there is also 8.0.0alpha1 which is out, and changes quite a bit of things.

[Carreau]

Merged, should be part of the next 7.31 release hopefully at end of month-ish.

[bnavigator]

Note that there is also 8.0.0alpha1 which is out, and changes quite a bit of things.

Yeah, we will have to defer releasing it on openSUSE a bit until all packages in the ecosystem are compatible with it. We didn't even update to traitlets 5 yet in order not to break compatibility for some (non-jupyter) packages which are still built for Python 3.6. Hopefully we can remove the Python 3.6 flavor soon after its EOL.