Thanks for taking the time to contribute to Git! Please be advised that the Git community does not use github.com for their contributions. Instead, we use a mailing list (firstname.lastname@example.org) for code submissions, code reviews, and bug reports. Nevertheless, you can use GitGitGadget (https://gitgitgadget.github.io/) to conveniently send your Pull Requests commits to our mailing list.
Please read the "guidelines for contributing" linked above!