improvement: enable require access

[eridal]

This will enable the module to be required as it were a
normal library, which will allow programmatic access to the API.

// require as module
const goodFirstIssue = require('good-first-issue')

// execute the bin script
goodFirstIssue.parse([ ... args ])

[eridal]

I found an unrelated issue, and though on adding the solution here, just is case comes handy for somebody..

The error happened when I was trying to generate the coverage report in html, with

npm t -- --coverageReporters=html

.. which typically will generate the coverage/index.html report, but handlebars was not happy about some properties.

The issue is well-known at jest repo (jestjs/jest#9396) so the workaround is to install handlebars v4.5.0

npm i -D handlebars@4.5.0

[eridal]

Any update on this one?

I find a bit ironic that this was my first attempt to submit an PR to an open source project .. anyways c'est la vie :)