GitLab version 17 implemented a change to the new runner registration workflow. The new workflow uses authentication tokens to register runners. The use of registration tokens has been deprecated and will be removed in the next major version. To prevent current workflows from breaking, the legacy method will remain enabled until the August update. Please review the following article for instructions on migrating to the new workflow and update your runners before Aug 7th, 2024:
https://docs.gitlab.com/ee/ci/runners/new_creation_workflow.html