merge queue: embarking 0.12.x (1587bb8), #535, #537, #540, #539 and #538 together

[mergify]

🎉 This pull request has been checked successfully and will be merged soon. 🎉

Branch 0.12.x (1587bb8), #535, #537, #540, #539 and #538 are embarked together for merge.

This pull request has been created by Mergify to speculatively check the mergeability of #538.
You don't need to do anything. Mergify will close this pull request automatically when it is complete.

Required conditions of queue default for merge:

• check-success=ci-passed

Required conditions to stay in the queue: None

---
previous_failed_batches: []
pull_requests:
  - number: 538
...