A base image for docker with steamcmd installed to build dedicated servers that is updated frequently.
The image works and is built on a daily base. I added an example dockerfile on how you can build a game server.
Docker Hub: https://hub.docker.com/r/snickch/steamcmd
Edit January 2021: If you start from scratch it may be better to use the steamcmd image (https://hub.docker.com/r/steamcmd/steamcmd) which is available with different tags (like Alpine). It should also be updated every 6 hours.