Add dependants test

[hongaar]

Would be really powerful if we could add a test suite for external projects using vorpal, essentially running their tests before/after any change in our code.

Example implementation: https://github.com/emberjs/data/blob/master/bin/test-external-partner-project.js

We can choose projects from this list: https://www.npmjs.com/browse/depended/vorpal

Of course, any project we choose to test should have a passing test suite.

Potential projects

• https://www.npmjs.com/package/@commitlint/prompt
• https://www.npmjs.com/package/@frctl/fractal (abandoned?)