[FEATURE] Grant members access through CLI

[a-nldisr]

Is your feature request related to a problem? Please describe.
UI allows granting permissions to users per project, and would like the same functionality in Doppler CLI

Describe the solution you'd like
Doppler CLI supports the same functionality as UI

Describe alternatives you've considered
Terraform, but it does not support it

[watsonian]

@a-nldisr Thanks for your request here! This is definitely something we'd like to support in the future. There's currently no API for it, which is the main reason there's no CLI or Terraform support. We don't currently have a timeline for this, but it is definitely on our radar!