deps(example): bump next

Bumps the dependencies group in /examples/nextjs-authjs-5 with 1 update: [next](https://github.com/vercel/next.js).


Updates `next` from 14.2.16 to 15.0.1
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.16...v15.0.1)

---
updated-dependencies:
- dependency-name: next
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dependencies
...

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