Update libgit2 binaries to 146b4d1

Work in Progress

This PR contains changes to update LibGit2Sharp on top of libgi2 at commit 146b4d1. I think there are other changes we are waiting on in lg2 before we take new lg2 binaries.

https://github.com/libgit2/libgit2/compare/11f8336...146b4d1