You can install it on OSX with Homebrew:

    brew install https://raw.github.com/asaph/homebrew/2897329686d905fc357c5e2e87597c8f6a8e9cd1/Library/Formula/git.rb

But they want to wait a few days to ensure there’re no bugs found [1] before adding it to the main repo.

[1]: https://github.com/Homebrew/homebrew/pull/26734