GitHub connection doesn't work behind authenticated proxy

[csmager]

The Octokit client created via the Fake.Tools.GitHub API uses the default proxy, but it doesn't pass on the credentials so you get a 407 Proxy Authentication Required error.

This proxy can explicitly be configured when creating the HttpClient (we'd set it here), but we'd need to decide how to approach this. I think we can do either of these (or both):

1. We can add additional createClient function(s) that accept an IWebProxy option. Not sure I like this as it rather ties your build script to the environment.
2. As suggested in Default Proxy issues dotnet/runtime#25745 (comment), all we should have to do is make sure the DefaultProxyCredentials are set on the HttpClientHandler and the system config should 'just work'.

[csmager]

Just noticed we still target net462 and DefaultProxyCredentials doesn't exist there. Might need an alternative!

[matthid]

@csmager To be honest: I have no idea what the best way forward is. Considering this might hit other modules as well we should aim for an approach which works for others as well.
Can you send a PR for approach 2?

[csmager]

Yes, will look into it. Unfortunately seems a little trickier than hoped given that property doesn’t exist in net462. I’m curious why we target that as well as netstandard2.0?

[matthid]

I don't think we really need net462 support, we add it to make the modules more useful (all FAKE modules/libraries can be used from regular .NET projects as well)

[csmager]

Ok. It's fairly easy just to add #ifdef NETSTANDARD2_0 and do what we need in there. Just need to find a willing colleague to do some testing to prove it solves the problem.