Link to Contributor Covenant on README is broken

[CaioCSdev]

The link on the readme points to an unexisting file https://github.com/elpassion/grape-cli/blob/master/contributor-covenant.org

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/elpassion/grape-cli. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](contributor-covenant.org) code of conduct.

I think I know which contributor covenant you are talking about, but it's better if you specify it 😄