v2.13.1.windows.6

MinGit for Windows v2.13.1(6)

This is a MinGit-only release; compared to v2.13.1(4) (v2.13.1(5) was
built incorrectly and is hence no longer publicly available), there are
no patches in Git's source code, but all dependencies are updated. Most
importantly, Git Credential Manager is at v1.14.0 (including support for
TLS 1.2) and OpenSSL is now at v1.0.2n, fixing two CVEs. Those two CVEs
do not realistically affect Git for Windows, but you know, CVEs.