Windows: `Repository.Clone` fails from a newly created repo in the temporary path

[kitbellew]

Please see the test and the comments in #742.

[kitbellew]

Fixed in libgit2/libgit2#2399. It would really be nice to have a new nuget soon, as the current one won't work in our case.

[nulltoken]

@kitbellew Don't worry, I'm on it 😉

[nulltoken]

Should be fixed as part of #751