Reviving OTA-98 with tighter scoping. ART will remain responsible for candidate PR creation and merging, since they create the candidate releases. ART also pushes errata. We'll watch errata via DataGrepper, or polling, or whatever, and auto-file fast PRs labeled to automatically merge (in this space, OTA-155 and OTA-262). This will save us from the annoyance of rebasing on conflicts, although that isn't all that frequent for fast. We will also file our own stable and EUS PRs (related to ART-2460), which will save us even more rebase conflicts (these happen pretty much every time today, with over a week between ART stable PR creation and the PR landing). Once we get phased rollouts (OTA-215), the fast/stable/eus PR will be a single PR that should be auto-created and auto-landed at public-errata time.