FIX: Reject any non-array, non-ns datetimes and timedeltas

[brisvag]

Done at euroSciPy2022! Fixes #48312.

On suggestion of @jorisvandenbossche, we opted to raise an error instead of converting to [ns] in order to make it easier in the future to add support for other granularity levels.

co-author: @Kislovskiy

• closes BUG: timedelta64[s] series constructor isn't equal with alternative constructor using to_timedelta unit='s' #48312
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[pep8speaks]

Hello @brisvag! 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 2022-09-05 09:54:15 UTC

[github-actions]

This pull request is stale because it has been open for thirty days with no activity. Please update and respond to this comment if you're still interested in working on this.

[brisvag]

I don't know how to solve the build error without help, unfortunately, so I would appreciate some suggestions.

[mroeschke]

Thanks for the pull request, but it appears to have gone stale. Additionally, it appears this behavior may head in a different direction (#48312 (comment) - happy to have your input!) Closing until the discussion is resolved there