[CI] Update changelog MR generation to pass Danger checks
Description
This MR updates the template for the changelog MR description to pass the Danger checks. It also adds the required labels and assignee.
Also spotted some leftover functionality related to the spec file which I removed.
Checklist
-
Documentation reflects the changes made. -
Merge Request title is clear, concise, and suitable as a changelog entry. See this link
References
Closes #1252 (closed)
Edited by Niels Alexander Buegel