build(deps-dev): bump gulp-load-plugins from 1.5.0 to 1.6.0

Bumps [gulp-load-plugins](https://github.com/jackfranklin/gulp-load-plugins) from 1.5.0 to 1.6.0.
- [Release notes](https://github.com/jackfranklin/gulp-load-plugins/releases)
- [Commits](jackfranklin/gulp-load-plugins@1.5.0...1.6.0)