wishlist: get git revision of other folders

[ferdymercury]

I often have small projects where I include big external libraries that are themselves git repositories in /opt.
In those cases, it would be nice to 'read' the commit sha of those folders.

To achieve that, I guess that this line should take a variable argument, (with default value as now):
https://github.com/rpavlik/cmake-modules/blob/main/GetGitRevisionDescription.cmake#L87

[ferdymercury]

This works for me, but is backward-incompatible. Not sure if there is a way to specify a default argument to get the old behavior:
ferdymercury@c4e57ba