docs: update command docs for Duo CLI beta release

Uma Chandranrequested to merge
uc/duo-cli-beta-release into main

Description

Companion update to Docs: GitLab Duo CLI beta release (gitlab!228916 - merged) for the GitLab Duo CLI beta release.

Keeping this in draft until we confirm the new beta requirements (minimum GitLab version and enabling beta features), and until someone tells me we're ready to go.

Related issues and merge requests

Edited by Uma Chandran

Merge request reports