This is about Terraform CLI Workspaces - not Terraform Cloud Workspaces. Those are different things for historic reasons. Hashicorp article

So you can have 2 projects linked to the same directory but using different workspaces, like this:

projects:
- name: dev
  branch: /main/
  dir: ./
  workspace: dev
  terraform_version: v0.11.0
- name: prod
  branch: /main/
  dir: ./
  workspace: prod
  terraform_version: v0.11.0

Example repository: https://github.com/diggerhq/digger_demo_workspaces/

ProjectsPR-level locks