Please add cl-diskspace

cl-diskspace: A Common Lisp feature to list disks with command line tool df(Linux/Mac) or GetLogicalDrives(Windows), and get disk space information using statvfs(Unix/Linux/Mac) or GetDiskFreeSpace(Windows), supports Unix/Linux/Mac/Windows.

[https://github.com/muyinliu/cl-diskspace](https://github.com/muyinliu/cl-diskspace)