Run only specified cops

Lint Ruby files.
More information: <https://docs.rubocop.org/rubocop/usage/basic_usage.html>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

rubocop --only {{cop_1}} {{cop_2}}

click the source code to copy install rubocop on any operating system with command-not-found.com