fix pgadmin workstation name (#2088)

The generated name did not follow the pattern of the other.

docker-compose.yml

@@ -597,7 +597,6 @@ services:
 
 ### pgAdmin ##############################################
     pgadmin:
-      container_name: pgadmin
       image: dpage/pgadmin4:latest
       environment:
         - "PGADMIN_DEFAULT_EMAIL=${PGADMIN_DEFAULT_EMAIL}"