Bors is going away:

The geo team has converted their repo to use GitHub Merge Queues. Seems like following their lead and not having to host our own bors infrastructure is the easiest path forward.

Per this discussion, we can use the following as references for the migration:

• Delete bors.toml in favor of GitHub merge queues geo#1037
• Add a failing test to check that merge queues work proj#179 (comment)

We will need to determine the process impacts, i.e. what do we need to change in the way we review, accept, and merge PRs.