Add Renovate configuration

Configure automated dependency updates using Doma framework's shared Renovate config.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: nakamura-to

renovate.json

@@ -0,0 +1,5 @@
+{
+  "extends": [
+    "github>domaframework/renovate-config"
+  ]
+}