Add upgrade note for merge request diff commits
What does this MR do and why?
Add an upgrade note to bring attention to finalizing the migrations that started with #334394 (closed).
This is the equivalent note to the one we are adding to the Release Notes with gitlab-com/www-gitlab-com!93753 (merged)
Related issues: #339139 (closed) #331823 (closed)
MR acceptance checklist
This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.
-
I have evaluated the MR acceptance checklist for this MR.