Upgrade minimist to 0.2.1

[mKeRix]

Fixes #7 - vulnerability in dependency:
https://snyk.io/vuln/SNYK-JS-MINIMIST-559764

I created a new branch from commit d4eff0f called v0.x for this fix. Unfortunately I can't create a PR based on a non-existent branch on your repo, so I would appreciate it a lot if you could create a branch off that commit as well, merge this PR there and then release v0.5.2 to npm.

[karlhorky]

Edit: Use mkdirp@0.5.3 - the problem is fixed there.

For anyone looking for a fix for the interim, using Yarn Resolutions you can specify this version number, even though it doesn't match the semver range of mkdirp.

Add this to your package.json if you're using Yarn and run yarn to update your lockfile:

  "resolutions": {
    "**/mkdirp/minimist": "0.2.1"
  }

[canpolatoral]

When will you merge this pull request?

[JaymoKang]

@isaacs

[LinusU]

This have already been released as 0.5.3 on Npm, please see #7 for more details.

[mKeRix]

Thanks for the fix @isaacs!