Update rubocop requirement from 1.12.1 to 1.13.0 (#49)
Update rubocop requirement from 1.12.1 to 1.13.0 (#49)

Updates the requirements on [rubocop](https://github.com/rubocop/rubocop) to permit the latest version.
- [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/v1.12.1...v1.13.0)

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

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
mattbrictson/pgcli-rails,mattbrictson/pgcli-rails