Should we start using merge queues?

[gfellerph]

https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/configuring-pull-request-merges/managing-a-merge-queue

Goal: remove the need for the 🚂 PR train PR which follows another one. label.

Context

Merge trains as we use them today, while reducing PR size, are hard to track and are blocking progress. With merge queues I would hope to not have to track connected PRs anymore because they're in the queue and will be merged when appropriate.