removed duplicate import of datetime

[PhilBrk8]

• Closes #xxxx
• I am familiar with the contributing guidelines
• Tests added
• Updates entries in docs/sphinx/source/reference for API changes.
• Adds description and name entries in the appropriate "what's new" file in docs/sphinx/source/whatsnew for all changes. Includes link to the GitHub Issue with :issue:`num` or this Pull Request with :pull:`num`. Includes contributor name and/or GitHub username (link with :ghuser:`user`).
• New code is fully documented. Includes numpydoc compliant docstrings, examples, and comments where necessary.
• Pull request is nearly complete and ready for detailed review.
• Maintainer: Appropriate GitHub Labels (including remote-data) and Milestone are assigned to the Pull Request and linked Issue.

two import statements of datetime:
import datetime
import datetime as dt

in the code, 'datetime' was only used once, so I changed it to dt and removed the redundant import

[cwhanse]

Looks fine to me, thanks @PhilBrk8

[cwhanse]

In the future, it is a good practice to prepare changes in a branch, rather than in your main branch. If you use git at the command line, the sequence is:

1. git checkout main
2. git pull upstream main - to be sure you start from the latest, upstream points to github.com/pvlib/pvlib-python.git
3. git checkout -b - make a new branch for the changes

Now edit / git add / git commit / git push etc. and then submit the new branch as your PR.

[AdamRJensen]

Thanks @PhilBrk8!