chore: enable CodeRabbit auto-review on release-* branches (#12936)

Adds release-.* to reviews.auto_review.base_branches so PRs targeting
release branches (e.g. release-1.9.2) receive the same auto-review as
PRs targeting main.

Author: ogabrielluiz

.coderabbit.yaml

@@ -36,7 +36,8 @@ reviews:
     ignore_title_keywords: []
     labels: []
     drafts: false
-    base_branches: []
+    base_branches:
+      - "release-.*"
   finishing_touches:
     docstrings:
       enabled: true