Use rulesets to lock branches when retiring a branch

Author: ryanjbaxter

.github/workflows/retire-branch.yml

@@ -140,9 +140,12 @@ jobs:
           echo "Branch:     $BRANCH"
           echo ""
 
-          # Look for an existing "Retired Branch Lock" ruleset on this repo.
+          # Look for an existing repo-level ruleset with this name.
+          # Filtering by source_type=="Repository" avoids matching org-level rulesets
+          # (which also appear in this list but cannot be patched via the repo API).
           RULESET_ID=$(gh api "repos/${REPO}/rulesets" \
-            | jq -r --arg name "$RULESET_NAME" '.[] | select(.name == $name) | .id')
+            | jq -r --arg name "$RULESET_NAME" \
+                '.[] | select(.name == $name and .source_type == "Repository") | .id')
 
           if [[ -z "$RULESET_ID" ]]; then
             echo "No existing '${RULESET_NAME}' ruleset found — creating one."