chore(deps-dev): bump @netlify/plugin-nextjs from 3.9.2 to 4.2.6

Bumps [@netlify/plugin-nextjs](https://github.com/netlify/netlify-plugin-nextjs) from 3.9.2 to 4.2.6.
- [Release notes](https://github.com/netlify/netlify-plugin-nextjs/releases)
- [Changelog](https://github.com/netlify/netlify-plugin-nextjs/blob/main/CHANGELOG.md)
- [Commits](https://github.com/netlify/netlify-plugin-nextjs/commits/v4.2.6)

---
updated-dependencies:
- dependency-name: "@netlify/plugin-nextjs"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]