⬆️ upgrade eslint to v9

Author: renovate[bot]

package.json

@@ -26,7 +26,7 @@
     "@typescript-eslint/eslint-plugin": "^5.33.1",
     "@typescript-eslint/parser": "^5.33.1",
     "autoprefixer": "^10.4.8",
-    "eslint": "^8.22.0",
+    "eslint": "^9.0.0",
     "eslint-config-next": "^14.0.0",
     "eslint-config-prettier": "^9.0.0",
     "eslint-plugin-mdx": "^3.0.0",