[Compose, Rspamd] Update Rspamd image to non-memleaking version

docker-compose.yml

@@ -73,7 +73,7 @@ services:
             - clamd
 
     rspamd-mailcow:
-      image: mailcow/rspamd:1.78
+      image: mailcow/rspamd:1.79
       stop_grace_period: 30s
       depends_on:
         - dovecot-mailcow