ci: update actions/checkout to v5 in Claude reusable workflow

- Update actions/checkout from v4 to v5 in claude-review-reusable.yml
- Ensures compatibility with latest GitHub Actions features and security updates
- v5 is the current latest stable release of actions/checkout

Author: tianjianjiang

.github/workflows/claude-review-reusable.yml

@@ -33,7 +33,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 1