Update suzuki-shunsuke/github-action-renovate-config-validator action to v2.1.0 (#2976)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/renovate-validation.yml

@@ -44,6 +44,6 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v6
       - name: Validate
-        uses: suzuki-shunsuke/github-action-renovate-config-validator@v2.0.0
+        uses: suzuki-shunsuke/github-action-renovate-config-validator@v2.1.0
         with:
           config_file_path: .github/renovate.json