`lint` should allow `ref` specification

Problem to solve

The CI Lint API accepts a ref option but this is not present in the CLI options leading to invalid output.

Proposal

Add support for the ref option.

Further details

$ glab ci lint -h
Checks if your `.gitlab-ci.yml` file is valid.

USAGE
  glab ci lint [flags]

INHERITED FLAGS
      --help              Show help for command
  -R, --repo OWNER/REPO   Select another repository using the OWNER/REPO or `GROUP/NAMESPACE/REPO` format or full URL or git URL

$ glab -v
glab version 1.31.0

Links / references

https://docs.gitlab.com/ee/api/lint.html