appveyor zip artifact is not compatible with macos

[vors]

I was hoping to grab a dev build, because of the Ctrl+C issue on 2.0.0-beta-1
But this is how it looks like unzipped on mac

[lzybkr]

Isn't this a bug in Compress-Archive?

[vors]

It's a dotnet problem, but maybe it's worth to use 7z in appveyor to workaround it for now.
https://docs.microsoft.com/en-us/dotnet/framework/migration-guide/mitigation-ziparchiveentry-fullname-path-separator

Let me try it out and send PR if it works

[vors]

ah, you are using invoke-build. That makes things harder.

I just merged PowerShell/platyPS#362 to fix the same issue in platyPS but it was more straightforward there.
I guess it doesn't worth to keep it open, eventually we will get dotnet full v461 images in appveyor and it will resolve.