Use our org-wide Renovate preset

[woodruffw]

Summary

This switches the preset to https://github.com/astral-sh/renovate-config, which is a superset of the config:recommended preset (with cooldowns added).

Test Plan

No functional changes.

[woodruffw]

Note: I manually validated this (from the repo root) with:

docker run --rm -it -v $(pwd):/workspace -w /workspace renovate/renovate renovate-config-validator ".github/renovate.json5"

...however that doesn't seem to have recursively validated the preset. I'm going to confirm that it does (or figure out how to) before merging here.

Edit: well... renovatebot/renovate#30968

I validated the preset itself in its own repo, so by composition the two should be okay.

[ntBre]

Does this special branch name validation work on GitHub? (I defer to you, just noticed this when skimming the docs)

[woodruffw]

Does this special branch name validation work on GitHub? (I defer to you, just noticed this when skimming the docs)

Oh, nice! Yeah, I bet so, let me re-PR this with that branch name.

[woodruffw]

#21759