fix: package.json & yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-NANOID-8492085
- https://snyk.io/vuln/SNYK-JS-ROLLUP-8073097

package.json

@@ -52,7 +52,7 @@
     "markdown-it-image-lazy-loading": "^1.2.0",
     "markdown-yaml-metadata-parser": "^3.0.0",
     "normalize.css": "^8.0.1",
-    "nuxt": "^3.6.5",
+    "nuxt": "^3.15.0",
     "typescript": "^5.1.6",
     "uslug": "^1.0.4",
     "vue": "^3.4.21",