Build for ARM platforms

[goldkin]

Over in https://github.com/Zarby89/Enemizer/blob/master/EnemizerCLI.Core/publish.bat, it should also be possible to build for ubuntu.16.04-arm. The primary motivation here would be to run Enemizer on a Raspberry Pi, which I've been working on for a multiworld server I've been running.

I tried this with VS2019 and Mono unsuccessfully (missing dependencies and case-sensitive file system woes, respectively), so I'm pretty sure this currently needs VS2017 to work.

Would it be possible to give this build target a go and publish the binary if it works?

[sosuke3]

Feel free to make a PR if it works