Trying something new: "Merge queue"

Hi folks! You might have seen me adding a new "merge queue" label to PRs.

This specifically changes how we land PRs. The idea is that we batch up 1-5 PRs that are ready to land in a merge queue, and the next available maintainer can apply them locally, one at a time, making sure they work (Passes tests, runs in docker-compose, & the CLI works.) If a merge queue PR fails to merge, if we can write a quick fix to get things upright again, we'll do so and commit it and move on to the next item. If we can't get it to work, we'll take the merge queue label off the PR and request changes. The goal is that we have less churn due to bugs introduced while we're adding tests.

I'm doing a test run of this to see if it helps out! If it does, we'll formalize the process in a document. Thanks for your patience, all :heart: