Bump rubocop from 1.25.1 to 1.26.0 (#333)
Bump rubocop from 1.25.1 to 1.26.0 (#333)

Bumps [rubocop](https://github.com/rubocop/rubocop) from 1.25.1 to 1.26.0.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop/rubocop/compare/v1.25.1...v1.26.0)

Co-authored-by: Dependabot <8254d1186852c26c9fb3d343db6a5be86317fea9@github.com>
activeadmin/arbre,activeadmin/arbre