Add support for C# / NetStandard about dependabot-core

[deinok]

Okey, tag me when you start working on it and i will give you a hand

[greysteil]

Thanks @deinok!

We'd love to add C# support, but are currently blocked by our own expertise on it (basically, I don't know C#!). If you'd like to help out I'd be totally up for working on it with you, but otherwise it's likely to be a bit of a wait.

There's an issue tracking this (and Java support, which I really need to get over the line...) at https://github.com/dependabot/feedback/issues/33, so I'm going to close this.

[deinok]

@greysteil Well, I can give with how to conceptualy do it but I don't think I can send a PR (Im dont know Ruby).

So I can writte the algorithm of how to check everything and you can "port" it to Ruby if you want.
Let me know it ;)

[greysteil]

Sounds good to me! Let me get the Java beta out and I'll hit you up with some questions / bits that need to be written in C#.