Rebase the pull request on top of its base branch.
The rebase action makes Mergify rebase the pull request on top of its base
branch. This is useful when you want to ensure that your pull request is always
up-to-date with the latest changes from the base branch.
To rebase, Mergify needs to impersonate a GitHub user. You can specify the account to use with this option. If no bot_account is set, Mergify picks the pull request author. The user account must have already been logged in Mergify dashboard once.