dep: remove mkdirp dependency

[rharriso]

What / Why

• dep: mkdirp hasn't been updated in 4 years, and node's fs library has had a recursive option for fs since v10.12 (oldest active LTS version). Additionally mkdirp depends on a version of library minimist that has a minor vulnerability associated.

Refs:

• https://nodejs.org/api/fs.html#fs_fs_mkdir_path_options_callback
• https://npmjs.com/advisories/1179

[ThomasThelen]

Any status on this? @rharriso, can you fix the conflict and maybe the maintainers won't have an issue merging?

[rharriso]

Freebased.