Create a GitHub Workflow to auto-run `generate.py` perodically

[ilovelinux]

The site is outdated right now.

A GitHub Workflow that:

• Periodically runs generate.py.
• If there are updates, open a PR.
• The PR will be merged by hand.

Would solve the issue.

Useful resources:

• https://github.com/peter-evans/create-pull-request