Have URLs periodically checked

[cansavvy]

Purpose/implementation Section

What changes are being implemented in this Pull Request?

This is a start to having a GHA that will check URLs periodically on a course without being provoked.

A few things we have to develop here:

1. We probably want it to make an issue if there's a URL error found.
2. If no error is found, we want it to clean up the preview branch and everything it does.

The last bit I have to put in here is if an issue is already open for broken URLs, we don't want to create another one. There doesn't seem to be a convenient GitHub Action for this, so I'm going to have to write a GitHub API accessing script to do it myself. I'll add it to the github-helpers or cow package.

I tried https://github.com/nickderobertis/check-if-issue-exists-action and https://actions-cool.github.io/issues-helper/advanced#find-issues but both assume the GitHub Action you are running is being triggered by an issue based trigger which is not what is happening for us.

[github-actions]

Re-rendered previews from the latest commit:

• See preview of Bookdown here
• See preview of Coursera/Leanpub version here
• Download the preview of .docx file

Updated at 2024-02-29 with changes from 8642465

[github-actions]

No spelling errors! 🎉
Comment updated at 2024-02-29 with changes from 8642465

[github-actions]

⚠️ broken urls ⚠️
There are broken urls that need to be addressed.
Click here ➡️ for broken urls errors! ❗
Add errors that aren't errors to the resources/ignore-urls.txt file of this repo.
If you are having troubles see this guide
Comment updated at 2024-02-29 with changes from 8642465