Corrected instruction in section "Jenkins-to-GitLab authentication", based on https://gitlab-docs-d6a9bb.gitlab.io/ee/user/permissions.html?utm_source=chatgpt.com#repository

Testing done

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests that demonstrate the feature works or the issue is fixed