Adds k parameter to temperature.ross

[ramaroesilva]

• Closes pvlib.temperature.ross could accept ross parameter as a NOCT alternative #2506
• 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.

I think the issue is clear enough.

[ramaroesilva]

In #2506 @cwhanse mentions that it is difficult to find the 1981 paper from Ross, to which @kandersolar provided a wayback machine url. Should I add it to the documentation of temperature.ross? If so, how?

[RDaxini]

Thanks for your contribution @ramaroesilva
I added a few suggestions for formatting the docstring and references. Have a look, and if you look under the "files changed" tab you can "add suggestion to batch" and implement more than one suggestion in a single commit

[cwhanse]

@ramaroesilva if you can fix the merge conflicts in the whatsnew file, we can launch the CI. To fix the conflicts, just keep both sets of lines - this sometimes happens when two PRs are adding lines at the same position.

[ramaroesilva]

@ramaroesilva if you can fix the merge conflicts in the whatsnew file, we can launch the CI. To fix the conflicts, just keep both sets of lines - this sometimes happens when two PRs are adding lines at the same position.

@cwhanse merge conflict fixed :-)

[cwhanse]

You can ignore the test failure for py3.9

[kandersolar]

Thanks @ramaroesilva!