Remove the `static-websites` GitHub action

[marcoieni]

We maintain a GitHub Action called static-websites that uploads a static website to GitHub Pages and (optionally) invalidates the cache of a CloudFront distribution. This action is used a few times in the rust-lang organization, but only rust-lang/thanks makes use of the cache invalidations.

Since GitHub now supports and encourages uploading static websites as artifacts, we want to refactor the workflows that use the static-websites action and replace it. Once that has been done, we can remove the action from this repository.

For each workflow that uses this action, we need to:

1. Replace the usage of static-websites with actions/upload-github-pages-artifact to upload the pre-built archive
2. Add a new deploy job as per the documentation for actions/deploy-github-pages-site

Repositories

The following repositories need to be updated:

• [ ] rust-lang/async-book https://github.com/rust-lang/async-book/pull/231
• [ ] rust-lang/polonius
• [ ] rust-lang/rust-forge
• [ ] rust-lang/wg-async

The rust-lang/thanks repository is slightly different, since that uses a CloudFront distribution. Replacing the static-websites action in this repository will require more steps and help from an administrator.

• [ ] Add a CNAME file for thanks.rust-lang.org (see Managing a custom domain for your GitHub Pages site)
• [ ] As an admin, change the DNS record to point to GitHub Pages
• [ ] As an admin, remove the CloudFront distribution once it is no longer used
• [ ] Replace the static-websites action as per the instructions above

Resources

• Discussion in Zulip

For maintainers

• [ ] evaluate if we should close https://github.com/orgs/rust-lang/projects/24/views/1?pane=issue&itemId=24038173