Bump @unleash/nextjs from 1.5.0 to 1.6.0

Bumps [@unleash/nextjs](https://github.com/Unleash/unleash-client-nextjs) from 1.5.0 to 1.6.0.
- [Release notes](https://github.com/Unleash/unleash-client-nextjs/releases)
- [Commits](Unleash/unleash-client-nextjs@v1.5.0...v1.6.0)

---
updated-dependencies:
- dependency-name: "@unleash/nextjs"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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