chore(deps): update dependency nuxt to v3

Author: renovate[bot]

docs/package.json

@@ -10,7 +10,7 @@
   },
   "dependencies": {
     "@nuxt/content-theme-docs": "^0.11.1",
-    "nuxt": "^2.15.8"
+    "nuxt": "^3.9.1"
   },
   "devDependencies": {
     "vue-plausible": "^1.3.1"