Convert BaseResource.save to return a promise.
Review Request #11642 — Created June 2, 2021 and submitted — Latest diff uploaded
This change updates the save machinery for various resources to use
promises and async/await instead of callbacks.
- Ran js-tests.
- Manually tested API token creation, comment editing, review request
field editing, post-commit review request creation, ship-it revocation,
and file attachment uploading.