Update onboarding.md

[ahoecherl]

DQL-<NUM>: <TITLE>

<DESCRIPTION>

✅ Pre-Merge Checklist

All boxes must be checked before the Pull Request is merged. This checklist has to be completed by the reviewer.

• The CI pipeline has passed (this is enforced by GitHub)
• Code Review
  • The code has been manually inspected by someone who did not implement the feature
• The PR implements what is described in the JIRA-Issue
• The new feature has been tested by the reviewer on his local machine
• A deployment to the dev environment has succeeded. If possible, ensure that the feature can be observed on the server.
• If required, any documentation is updated accordingly

💾 Merge Checklist

• The branch is merged to main using the "Squash and Merge" strategy following the commit message naming convention DQL-<NUM>: <TITLE>
• The branch is deleted after the PR is merged