Fix test

[hicom150]

To fix #6 mkdirp dependency has been required in order to create recursive directory paths.

It is true that from node 10 onward, native fs.mkdir has already included the recursive option, but with the intention to maintain node 8 compatibility I understand that adding mkdirp is a better solution 😉

[Borewit]

Addresses high severity vulnerability in lodash 4.17.11, https://www.npmjs.com/advisories/1065