[security]: remove mkdirp, we don't need it

[coolaj86]

mkdirp depends on minimist for the CLI

We actually don't care, because we don't rely on that functionality. HOWEVER, might as well nix it all the same. Node.js has had native mkdirp support since v10.12+.

See:

• https://nodejs.org/api/fs.html#fsmkdirpath-options-callback