Update libgit2
treea6f4570dca0ef353682873d58b7ed47cd0c2a3d7
-rw-r--r-- 600 .gitignore
-rw-r--r-- 1065 .gitmodules
-rw-r--r-- 639 .mailmap
-rw-r--r-- 231 .tgitconfig
drwxr-xr-x - Languages
-rw-r--r-- 3975 README.md
-rw-r--r-- 2323 appveyor.yml
-rw-r--r-- 6138 architecture.txt
-rw-r--r-- 3463 build.txt
drwxr-xr-x - contrib
drwxr-xr-x - doc
drwxr-xr-x - ext
-rw-r--r-- 1261 release.txt
drwxr-xr-x - src
drwxr-xr-x - test