* Upgrade to Ruby 2.7.0
* Upgrade Travis's Ruby as well
* Fix conflict
* Silence all Ruby 2.7 deprecation warnings in dev mode
* Silence dev and test unless CI
* Upgrade to Ruby 2.6.0
* Change Ruby version in guides and in travis
* Upgrade Rubocop
* Change Rubocop version for code climate
* Update .codeclimate.yml
* Update badge