Fix release merge script (#4273)

Co-authored-by: Ernesto García <[email protected]>

scripts/release/workflow/prepare-release-merge.sh

@@ -9,15 +9,18 @@ MERGE_BRANCH=merge/$GITHUB_REF_NAME
 git checkout -B "$MERGE_BRANCH" "$GITHUB_REF_NAME"
 
 # Get deleted changesets in this branch that might conflict with master
-readarray -t DELETED_CHANGESETS < <(git diff origin/master --name-only -- '.changeset/*.md')
+# --diff-filter=D - Only deleted files
+readarray -t DELETED_CHANGESETS < <(git diff origin/master --diff-filter=D --name-only -- '.changeset/*.md')
 
 # Merge master, which will take those files cherry-picked. Auto-resolve conflicts favoring master.
-git merge origin/master -m "Merge master to $GITHUB_REF_NAME" -X theirs
+# Ignore conflicts that can't be resolved.
+git merge origin/master -m "Merge master to $GITHUB_REF_NAME" -X theirs || true
 
 # Remove the originally deleted changesets to correctly sync with master
 rm -f "${DELETED_CHANGESETS[@]}"
 
-git add .changeset/
+# Only git add deleted files
+git ls-files --deleted .changeset/ | xargs git add
 
 # Allow empty here since there may be no changes if `rm -f` failed for all changesets
 git commit --allow-empty -m "Sync changesets with master"