Replace logger.warn w/ logger.warning

[zklaus]

Description

This replaces calls to logger.warn with logger.warning. The former has been deprecated since Python 3.3 and generates DeprecationWarnings that can make output particularly in debugging and testing more noisy than necessary.

Checklist - did you ...

As this is a purely internal change, I don't thing any of the following items apply.
Please do correct me if I am wrong.

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[zklaus]

pre-commit.ci autofix

[codspeed-hq]

CodSpeed Performance Report

Merging #5364 will not alter performance

_{Comparing zklaus:warn-to-warning (c07e306) with main (cdca0b4)}

Summary

✅ 3 untouched benchmarks

[jaimergp]

Thanks! Next one in line, this hack in conda 😂

[zklaus]

I can fire up the analogous conda PR. Thanks to @jaimergp's pointer, I found a simple ruff one-liner for this one.