fix pgadmin workstation name (laradock#2088)

ggirardi1 · bestlong · commit 83a24efa709d · 2019-04-19T07:54:13.000+08:00
The generated name did not follow the pattern of the other.
diff --git a/docker-compose.yml b/docker-compose.yml
@@ -597,7 +597,6 @@ services:
 
 ### pgAdmin ##############################################
     pgadmin:
-      container_name: pgadmin
       image: dpage/pgadmin4:latest
       environment:
         - "PGADMIN_DEFAULT_EMAIL=${PGADMIN_DEFAULT_EMAIL}"
