update ubuntu-latest reference

[markgoho]

ubuntu 22 is now ubuntu-latest

Why:

Closes #22132

What's being changed (if available, include any code snippets, screenshots, or gifs):

Changing what ubuntu-latest points to in the docs

Check off the following:

• [x] I have reviewed my changes in staging (look for the "Automatically generated comment" and click the links in the "Preview" column to view your latest changes).
• [x] For content changes, I have completed the self-review checklist.

[welcome[bot]]

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[cmwilson21]

@markgoho Thank you for opening a PR and linking it to your issue! ✨

I'll get this triaged for review! :zap:

[lucascosti]

Closing as per https://github.com/github/docs/issues/22132#issuecomment-1323108801 🙇‍♂️