up CI to use Centrifugo v6 (#301)

Author: FZambia

docker-compose.yml

@@ -2,15 +2,15 @@ version: '3.8'
 
 services:
   centrifugo:
-    image: centrifugo/centrifugo:v5.4.0
+    image: centrifugo/centrifugo:v6.0.0
     command:
       - centrifugo
     ports:
       - "8000:8000"
     environment:
       - CENTRIFUGO_CLIENT_INSECURE=true
-      - CENTRIFUGO_HTTP_STREAM=true
-      - CENTRIFUGO_SSE=true
-      - CENTRIFUGO_PRESENCE=true
+      - CENTRIFUGO_HTTP_STREAM_ENABLED=true
+      - CENTRIFUGO_SSE_ENABLED=true
+      - CENTRIFUGO_CHANNEL_WITHOUT_NAMESPACE_PRESENCE=true
       - CENTRIFUGO_CLIENT_CONCURRENCY=8
       - CENTRIFUGO_LOG_LEVEL=debug