ServerOs is never passed

[haringsrob]

Hello,

Before I create an issue, I ran into some device mapping errors. Mainly unknown server OS

After a bit of checking I found that here containerConfig, err := parse(flags, copts, "")

act/pkg/container/docker_run.go

Line 354 in 70e1e37

containerConfig, err := parse(flags, copts, "")

an empty string is passed.

Is there a reason to not have this implemented?

I may be able to make a pr for fixing this. In my local tests I hardcoded it to linux which allowed me to map devices.