Docker Compose Traefik 3 (#7219)

Use :3 instead of `3.0` to avoid having to update the documentation too often.
Follow-up of https://github.com/FreshRSS/FreshRSS/pull/6401

Docker/freshrss/docker-compose-proxy.yml

@@ -7,7 +7,7 @@ volumes:
 services:
 
   traefik:
-    image: traefik:3.0
+    image: traefik:3
     container_name: traefik
     restart: unless-stopped
     logging: