Remove gradle from ignoreDeps in renovate.json

Allow Renovate to manage Gradle version updates.

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

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

Author: nakamura-to

renovate.json

@@ -1,8 +1,5 @@
 {
   "extends": [
     "github>domaframework/renovate-config"
-  ],
-  "ignoreDeps": [
-    "gradle"
   ]
 }