MAINT: pandas 1.4: no longer use get_loc with method

[mathause]

• Closes pandas deprecates Index.get_loc with method #5721
• Tests added
• User visible changes (including notable bug fixes) are documented in whats-new.rst

Fixed as per @shoyer & @spencerkclark suggestion from #5721 (comment)

Now that pandas 1.4 is out it would be good to get this fixed (there are about 5000 warnings in our tests, mostly because of interp, though). Also leads to a warning in our docs which breaks them (although that can also be fixed with an :okwarning: directive).

[dcherian]

sphinx.errors.SphinxParallelError: RuntimeError: Non Expected warning in `/home/docs/checkouts/readthedocs.org/user_builds/xray/checkouts/6195/doc/user-guide/computation.rst` line 374

Sphinx parallel build error:
RuntimeError: Non Expected warning in `/home/docs/checkouts/readthedocs.org/user_builds/xray/checkouts/6195/doc/user-guide/computation.rst` line 374
[IPKernelApp] WARNING | Parent appears to have exited, shutting down.

RTD failure might be related (not obvious from looking at computation.rst)

[max-sixty]

Thanks @mathause , this looks great

[mathause]

RTD failure might be related

I just checked locally. This PR (+ #6194) fixes the doc build problem. It would require a lot of :okwarning: directives, so I suggest to merge this PR soonish instead of extending #6194.

[dcherian]

Thanks @mathause

[max-sixty]

I'll aim to do a release later