* Update authentication.md
Fix an example code that refers to undefined variables.
* Update authentication.md
use client_id and client_secret stored in auth_credential.
* Update authentication.md
Add missing imports
* Update authentication.md
Update for the latest auth lib.
---------
Co-authored-by: Lavi Nigam <98014943+lavinigam-gcp@users.noreply.github.com>
* fix: update authentication doc to correct some error and keep it consistent with latest codes
* Update docs/tools/authentication.md
---------
Co-authored-by: Sean Zhou <seanzhougoogle@google.com>
Co-authored-by: Sita Lakshmi Sangameswaran <sitalakshmi@google.com>