Updating authentication how-to entry

Author: niklarin

articles/cosmos-db/postgresql/TOC.yml

@@ -162,8 +162,8 @@
           href: howto-ingest-azure-data-factory.md
     - name: Manage
       items:
-        - name: Manage users
-          href: howto-create-users.md
+        - name: Manage Azure AD and Postgres authentication
+          href: how-to-configure-authentication.md
         - name: Schedule maintenance
           href: howto-maintenance.md
         - name: Start and stop cluster compute