- In all of the PRs that this Action triggered, the `tapioca-update`
  branch was >200 commits behind the latest `master`.
- As per https://github.com/Homebrew/brew/pull/8435#issuecomment-678546024,
  we shouldn't rely on the `Homebrew/actions/setup-homebrew` master
  (the `origin/master` ref) branch being up to date, so resetting to
  `origin/master` was a bad idea.
- A side effect of this is that when we raise PRs to change the Action,
  the PRs that it generates will include local commits. But functionally
  all we care about is the Action that runs on a schedule.