Docs website is down

[honno]

The gh-pages branch was accidentally deleted this morning (by someone who's username rhymes with Bono :thinking:), which left https://data-apis.org/array-api/ giving a 404 error.

I made and pushed a gh-pages branch with a local build of the spec, as well as re-running the latest publish CI job to no avail—in both instances I got "No [CircleCI] configuration was found in your project." (details). I don't recall having a CircleCI config in gh-pages repo too, but maybe we did? Checking the relevant PRs and discussions I don't believe so, but can't verify this. I also don't have access to the CircleCI account.

I think next steps is to:

• [x] Check this repo's settings (I don't have access) to see if any GitHub pages related setting needs to be re-checked/etc.
• [x] See if anyone has gh-pages locally and give a file diff of the remote branch.

[rgommers]

• Site is back up
• I've restored the gh-pages branch, which I had locally with history up to a week ago. It may miss the raw html for a couple of deploys, but that doesn't really matter
• I have also enabled branch protection for the gh-pages branch (in addition to main)

There was nothing else to no to fix CircleCI, the site came back up after the gh-pages branch was restored.