PR commit-queue is setting author to "evrg-bot-webhook"

The selected-tests project has been using commit-queue for a while, but yesterday the author for commits to master started showing up as "evrg-bot-webhook": https://github.com/mongodb/selected-tests/commits/master.

The same thing is happening on https://github.com/10gen/build-baron-tools/commits/master.

Previously, commits to master made by the PR commit queue set the author of the commit to the author of the PR that was being merged. This made it easier for me to track when my PRs had been merged.