[ECO-1594] Include upstream incorporation in DSS changelog

[alnoki]

Description

Update DSS v2.1.0 changelog for incorporation of upstream changes

Testing

Local docs serve

Checklist

• [x] Did you update relevant documentation?
• [x] ~Did you add tests to cover new code or a fixed issue?~
• [x] Did you update the changelog?
• [x] Did you check off all checkboxes from the linked Linear task?