[LibGit2_jll] Update to v1.7.2 (#53467)
Memo to self:
* update version number in `stdlib/LibGit2_jll/Project.toml`
* update test result in `stdlib/LibGit2_jll/test/runtests.jl`
* update version number and commit sha in `deps/libgit2.version`
* refresh checksums with `make -f contrib/refresh_checksums.mk -j libgit2`
