Update dependency next to v15

Author: renovate[bot]

frontend/package.json

@@ -12,7 +12,7 @@
   },
   "dependencies": {
     "bulma": "^0.9.1",
-    "next": "^10.0.3",
+    "next": "^15.5.0",
     "prismjs": "^1.22.0",
     "react": "^16.14.0",
     "react-dom": "^16.14.0"