git: Update to Git v2.41.0.gl1

We have recently upstreamed a new -Z option for git-cat-objects(1) that will cause it to NUL-terminate its output. This is required so that it becomes possible to request revisions from it that contain embedded newlines while using one of the --batch modes.

We have backported this patch series into Git v2.41.0.gl1, so let's upgrade to that version so that we can start using this option.