Add Work-in-Progress prompt

[hassankhan]

Description

What is the use case that should be solved?

The prompter should ask whether the commit is work-in-progress. If so, it should prepend [WIP] to the subject header as follows:

fix(api): [WIP] changed API types

Similar or dependent issues:

• Add Work-in-Progress prompt cz-jira-smart-commit#10

Additional Data

Version of cz-github you're using: 1.0.5

Node Version: 8.11

Operating System: macOS 10.14