Added public-proxy for Traefik

Not sure if it actually makes a difference that it's listed, but I'll continue going with it until I know for sure.

templates/PHPMyAdmin/0/docker-compose.yml

@@ -31,9 +31,12 @@ services:
       {{- end}}
     networks:
       - db-admin # Used to be able to make secure, direct connections to other services in other stacks
+      - public-proxy # Used for the connection to the Traefik container for public access
     ports:
       - "${WEB_PORT}:80"
     restart: on-failure
 
 networks:
-  db-admin:
+  db-admin:
+  public-proxy:
+    external: true