Mergify `squash` command lost an original author of commits

[ihostage]

Docs: https://docs.mergify.com/commands/squash/#parameters
When I as maintainer write a command @Mergifyio squash [<commit message format>] in comment for PR, I don't want be an author of new commit of this PR. I think it should be an author of PR not comment.
See playframework/playframework#13044

[mkurz]

+1