chore(deps): bump eslint-config-next from 15.5.6 to 16.0.0

Bumps [eslint-config-next](https://github.com/vercel/next.js/tree/HEAD/packages/eslint-config-next) from 15.5.6 to 16.0.0.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/commits/v16.0.0/packages/eslint-config-next)

---
updated-dependencies:
- dependency-name: eslint-config-next
  dependency-version: 16.0.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

examples/app-router-showcase/package.json

@@ -20,7 +20,7 @@
     "@types/react": "^19",
     "@types/react-dom": "^19",
     "eslint": "^9",
-    "eslint-config-next": "15.5.6",
+    "eslint-config-next": "16.0.0",
     "typescript": "^5"
   }
 }