Add Superpower dependency as a maintained alternative to Sprache?

The Sprache Nuget package currently doesn’t seem to receive updates. Superpower is a recent parser combinator library that is based on Sprache. I think this would be a useful addition, since some exercises still recommend giving Sprache a try.

Could we add it as an alternative to the Dockerfile of the C# test runner? I can create a pull request if that would help.

Yes that would be perfectly fine. PR’s are appreciated.