Without this, we get a warning message from Traefik:

> INF Could not create a router for the container: too many services providerName=docker

Possibly due to the multiple services defined there without a single
explicitly-defined router.

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Related to: https://github.com/mautrix/facebook/issues/332

Fixes: https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3138