fix(deps): update dependency next to v14.2.21 [security]

Author: renovate[bot]

packages/code-du-travail-frontend/package.json

@@ -66,7 +66,7 @@
     "lit": "2.6.1",
     "lodash.deburr": "^4.1.0",
     "memoizee": "^0.4.15",
-    "next": "14.2.11",
+    "next": "14.2.21",
     "p-debounce": "^2.1.0",
     "prettier": "^3.3.3",
     "prop-types": "^15.8.1",