Prevent Changelog Merge Conflicts

Description

• Adds merge=union for changelog to prevent merge conflicts

Related Issues

• N/A

Checklist

• I have added a changelog entry to reflect the significant changes I made.

added typeimprovement label

requested review from @rbackx

assigned to @toberhuber

approved this merge request

added this merge request to the merge train at position 2

merged

mentioned in commit 9758f778

unassigned @toberhuber