chore(deps-dev): bump nightwatch from 2.6.5 to 2.6.6

Bumps [nightwatch](https://github.com/nightwatchjs/nightwatch) from 2.6.5 to 2.6.6.
- [Release notes](https://github.com/nightwatchjs/nightwatch/releases)
- [Commits](nightwatchjs/nightwatch@v2.6.5...v2.6.6)

---
updated-dependencies:
- dependency-name: nightwatch
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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