* Update rubocop requirement from ~> 0.67.2 to ~> 0.68.1

Updates the requirements on [rubocop](https://github.com/rubocop-hq/rubocop) to permit the latest version.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop-hq/rubocop/compare/v0.67.2...v0.68.1)

* Rerun rubocop --auto-gen-config

The cop Layout/IndexHash was renamed to Layout/IndentFirstHashElement
causing CI to fail. By rerunning the config generator this updates the
correct cop name so that Rubocop no longer fails in CI.