fix(deps): update dependency next to v15

Author: renovate[bot]

website/package.json

@@ -11,7 +11,7 @@
   },
   "dependencies": {
     "@theguild/components": "^6.5.3",
-    "next": "14.2.10",
+    "next": "15.0.1",
     "next-sitemap": "4.2.3",
     "react": "^18.2.0",
     "react-dom": "^18.2.0"