Update postgres_role description to remove consul from the role

Author: James Reed

doc/roles/index.md

@@ -133,7 +133,7 @@ Documentation on the usage of the PostgreSQL Roles can be found in [Configuring
 
 - **postgres_role** (`gitlab-ce`/`gitlab-ee`)
 
-  Enables the PostgreSQL and Consul services on the machine
+  Enables the PostgreSQL service on the machine
 
   *By default, enables no other services.*