* Added non-root user creation for SteamCMD in Dockerfiles for Ubuntu 18.04, 20.04, 22.04, and 24.04.
* Included a basic health check to ensure SteamCMD is operational.
* Updated README to correct "docker cli" to "Docker cli".
steamcmd update will only apply to root user. If non root user update is still downloaded. This update added 138MB layer to docker container and will probably not be used anyway.