`GitSource(...; unpack_target=dir)`appears to clone the repository to the wrong directory

[giordano]

It would be nice if we had a kwarg that let us rename the directory. We have unpack_target, but that would result in wine/wine-staging.

Originally posted by @Keno in JuliaPackaging/Yggdrasil#4127 (comment)

I'm not sure this is how this was meant to work, I believe we wanted unpack_target="wine" to clone the repo to /workspace/srcdir/wine. For example this is what ArchiveSource does.