The steamcmd update requires an extra 2GB of free disk space. The container seems to be using around 8.7GB, which results in a steam update failure of `Error! App '2394010' state is 0x226 after update job.` since there isn't enough space to grab the new version in a 10GB disk. Bumping this to 12GB should result in ~3.4GB of free space, so there is a small buffer for future update size increases.
