feat(classnames-order): group by responsive variant

[francoismassart]

Reorder by grouping responsive variants first

Description

Reading the thread from @adamwathan about the best way to structure your classes and markup with Tailwind CSS I though people might want to

Group responsive classes together by screen size (...)

setting the option groupByResponsive to true will do just that and then within each responsive variant group, it'll order classnames as you would expect.

Fixes #30

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• npm test

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have checked my code and corrected any misspellings