docs: Update docker documentation to add /sbin/conduwuit to examples

These will likely have to be updated when !1485 goes through.

Fixes: !1529

docs/deploying/docker-compose.with-caddy.yml

@@ -23,6 +23,7 @@ services:
         ### then you are ready to go.
         image: forgejo.ellis.link/continuwuation/continuwuity:latest
         restart: unless-stopped
+        command: /sbin/conduwuit
         volumes:
             - db:/var/lib/continuwuity
             - /etc/resolv.conf:/etc/resolv.conf:ro # Use the host's DNS resolver rather than Docker's.