Update libgit2
tree575c4daa4abd4f74c1f2692558a5c80ba9ed758c
-rw-r--r-- 458 .gitignore
-rw-r--r-- 975 .gitmodules
-rw-r--r-- 639 .mailmap
-rw-r--r-- 231 .tgitconfig
drwxr-xr-x - Languages
-rw-r--r-- 3974 README.md
-rw-r--r-- 2988 appveyor.yml
-rw-r--r-- 6137 architecture.txt
-rw-r--r-- 2589 build.txt
drwxr-xr-x - contrib
drwxr-xr-x - doc
drwxr-xr-x - ext
-rw-r--r-- 952 release.txt
drwxr-xr-x - src
drwxr-xr-x - test