ship core.autocrlf=true value in dugite-native for Windows

This was a useful feature in GitHub for Windows, which was built on an internal version of msysgit and, as such, had its own global Git configuration that could have autocrlf globally defaulted on.

It looks like GitHub Desktop is designed to only respect .gitattributes in a repository for CRLF handling (initializing every repository it creates with one); it would be nice if there were an option to enable automatic CRLF translation when .gitattributes is not present (an option that, I would add, should be enabled by default, as it was in GitHub for Windows), as I have a lot of existing repositories without .gitattributes that expect the platform’s Git client to manage this itself (a reasonable expectation that, again, was followed by For Windows).

[shiftkey]

@stuartpb we had a long discussion about this in #340 and added steps to get Git for Windows as close to Git Shell as possible in https://github.com/desktop/desktop/issues/340#issuecomment-302021683. We’ve decided to focus our resources on the UI side of Git and help support upstream efforts wherever possible, rather than competing with Git for Windows.

[stuartpb]

I just installed Git for Windows (with its autocrlf config), and I’m still seeing the out-of-place warnings I described earlier (saying line endings have changed specifically for files where they haven’t). I’ll file a new issue with repro steps for that.