TST: add test for compatibility with numpy datetime64
- [x] Closes #41617 
- [x] test added
- [ ] whatsnew entry 
Hello @ChrisAlbertsen! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



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

##### Comment last updated at 2022-02-10 06:51:57 UTC @github-actions pre-commit Thanks @ChrisAlbertsen 