Bump commander from 3.0.2 to 4.0.0 (#150)

Bumps [commander](https://github.com/tj/commander.js) from 3.0.2 to 4.0.0.
- [Release notes](https://github.com/tj/commander.js/releases)
- [Changelog](https://github.com/tj/commander.js/blob/master/CHANGELOG.md)
- [Commits](tj/commander.js@v3.0.2...v4.0.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -33,7 +33,7 @@
   "license": "MIT",
   "devDependencies": {
     "colors": "^1.3.3",
-    "commander": "^3.0.0",
+    "commander": "^4.0.0",
     "coveralls": "^3.0.2",
     "istanbul": "^0.4.5",
     "jsdoc-to-markdown": "^5.0.0",