After installation simply comment /rebase to trigger the action:
To configure the action simply add the following lines to your .github/main.workflow workflow file:
workflow "Automatic Rebase" {
  on = "issue_comment"
  resolves = "Rebase"
}
action "Rebase" {
  uses = "docker://cirrusactions/rebase:latest"
  secrets = ["GITHUB_TOKEN"]
}