Replace "member" with "principal" to fix failing test

Author: melaniedejong

iam/cloud-client/snippets/modify_policy_add_member.py

@@ -50,6 +50,6 @@ def modify_policy_add_member(
     # Your Google Cloud project ID.
     project_id = "test-project-id"
     role = "roles/viewer"
-    member = f"serviceAccount:test-service-account@{project_id}.iam.gserviceaccount.com"
+    principal = f"serviceAccount:test-service-account@{project_id}.iam.gserviceaccount.com"
 
     modify_policy_add_member(project_id, role, principal)