pass temperature, pressure to modelchain sol pos call

[Ahanmr]

This PR handles, the case where pressure or temp_air is not in weather, using the pvlib.tools._build_kwargs method, as keyword arguments. #893

• Closes Updated method of modelchain.ModelChain.prepare_inputs in modelchain.py #893 get_solarpostion in modelchain.prepare_inputs does not use weather data. #523
• I am familiar with the contributing guidelines
• Tests added
• Updates entries to docs/sphinx/source/api.rst 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 and Milestone are assigned to the Pull Request and linked Issue.

[Ahanmr]

@cwhanse How do I resolve the codecov error here?

[Ahanmr]

Since, the code successfully passes all checks except these two codecov tests.

[cwhanse]

@cwhanse How do I resolve the codecov error here?

Don't worry about it. codecov isn't hitting the 95% target due to raise statements, and a few untested lines that are outside this PR.

[cwhanse]

@Ahanmr just pinging you about this PR - can you add a line to the whatsnew v0.7.2 file, and add yourself to the Contributors section? Or if circumstances prevent you, I can do it for you.

[Ahanmr]

Yes @cwhanse ! I'll do this right away! Thank you!

[CameronTStark]

LGTM. Thanks @Ahanmr!