Merge branch 'jc/submodule-helper-avoid-zu' into jch

An accidental use of the '%zu' format specifier in 'git submodule--helper' has been corrected to use 'PRIuMAX' and cast the value to 'uintmax_t' to avoid portability issues. * jc/submodule-helper-avoid-zu: submodule--helper: avoid use of %zu for now