Actually truly really NOW actually for real really truly now actually fix docker compose in updater

updater/Dockerfile

@@ -20,6 +20,7 @@ RUN apt-get update && \
     rm -rf /var/lib/apt/lists/*
 
 # Add user to the docker group
+ARG DOCKER_GID
 RUN usermod -aG $DOCKER_GID www-data
 
 # Create .docker directory and set permissions