Bump @next/env from 13.5.6 to 14.2.8

Bumps [@next/env](https://github.com/vercel/next.js/tree/HEAD/packages/next-env) from 13.5.6 to 14.2.8.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/commits/v14.2.8/packages/next-env)

---
updated-dependencies:
- dependency-name: "@next/env"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

packages/next-sitemap/package.json

@@ -54,7 +54,7 @@
   },
   "dependencies": {
     "@corex/deepmerge": "^4.0.43",
-    "@next/env": "^13.5.6",
+    "@next/env": "^14.2.8",
     "fast-glob": "^3.3.1",
     "minimist": "^1.2.8"
   },