Document Node updates

[stucka]

When Github shifts to a different version of Node we start getting deprecation warnings. When appropriate updates exist, the fixes are relatively simple but sometimes difficult to find. You need to look in Github projects to see what the new correct version exists, if there actually is a Node 24 or whatever version yet. Then you need to fix the references to the version numbers in a bunch of spots.

References to look for in each thing:
actions/checkout
actions/setup-python
actions/download-artifact
actions/upload-artifact
biglocalnews/upload-files
slackapi/slack-github-action
stefanzweifel/git-auto-commit-action

Patch needed in main folder and in .github:
biglocalnews/upload-files.
Releasing a new version of biglocalnews/upload-files can be a little weird -- I think I've just been incrementing a whole version number (e.g., v3.0.0 to v4.0.0) but also re-releasing with a new major tag version tag (e.g., "v4"). Not sure that's the most direct way of doing it but it seems to be working.

Patches needed inside .github of these:
biglocalnews/bln-python-client
biglocalnews/warn-transformer
biglocalnews/warn-scraper
And a bunch of different spots in warn-github-flow -- be sure to look in .github/actions for biglocalnews/upload-files