fix(deps): update dependency next to v16 [security]

Author: renovate[bot]

website/package.json

@@ -13,7 +13,7 @@
   },
   "dependencies": {
     "@theguild/components": "9.8.0",
-    "next": "^15.3.3",
+    "next": "^16.0.0",
     "next-sitemap": "^4.2.3",
     "react": "^19.0.0",
     "react-dom": "^19.0.0"