I note this sentence "Periodically as you work check in your changes (to your branch; you can do this without requesting review):"
I think a better flow would be to make the YAML documents locally, run it through the YAML checker and at the end of the work day transfer it to a new branch and then put in a PR for it. If you did it like that there would be minimal chance that your branch would be behind as long as there is a quick review.
I note this sentence "Periodically as you work check in your changes (to your branch; you can do this without requesting review):" I think a better flow would be to make the YAML documents locally, run it through the YAML checker and at the end of the work day transfer it to a new branch and then put in a PR for it. If you did it like that there would be minimal chance that your branch would be behind as long as there is a quick review.