Update Git versions

I use GCK to do my development work. I saw that my Gitaly instance was breaking, looking at the logs I realized it is because I was using reftables. Git 2.45 introduced reftables, and we're already scheduled to have Git 2.46 to be released on 29th July 24.

Reftables is a new reference backend, and we plan to move all repositories to use reftables in the future in Gitaly. It would only make sense that we also update our Git versions here so that we can also test reftables locally.

Also, 2.36 is the current version and that was tagged two years ago 😓