[New git version] v2.48.0-rc1

[github-actions]

https://github.com/git/git/releases/tag/v2.48.0-rc1

[dscho]

Despite the quick brown-bag-paper fix backported via git-for-windows/msys2-runtime#80, there are still some inexplicable hangs in MSYS2 runtime v3.5.5. And since Git v2.48.0-rc1 already landed, I'll roll back Git for Windows' SDK to MSYS2 runtime v3.5.4 and Git for Windows v2.48.0 will not have MSYS2 runtime v3.5.5.