Bump commander from 2.20.3 to 4.0.1

Bumps [commander](https://github.com/tj/commander.js) from 2.20.3 to 4.0.1.
- [Release notes](https://github.com/tj/commander.js/releases)
- [Changelog](https://github.com/tj/commander.js/blob/master/CHANGELOG.md)
- [Commits](tj/commander.js@v2.20.3...4.0.1)

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

Author: dependabot-preview[bot]

package.json

@@ -67,7 +67,7 @@
     "browserify-imgify": "^0.0.1",
     "chromedriver": "75.1.0",
     "clean-css-cli": "^4.1.6",
-    "commander": "^2.15.1",
+    "commander": "^4.0.1",
     "cross-env": "^6.0.3",
     "css-loader": "^0.28.11",
     "es3ify-loader": "^0.2.0",