Update suzuki-shunsuke/github-action-renovate-config-validator action to v2.1.0 (#167)

Author: renovate[bot]

.github/workflows/validate-renovate-config.yaml

@@ -15,4 +15,4 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Validate Renovate config
-        uses: suzuki-shunsuke/github-action-renovate-config-validator@v2.0.0
+        uses: suzuki-shunsuke/github-action-renovate-config-validator@v2.1.0