Added ARIA: Application Role

[ShreyaPrasad1209]

What Changed

• [x] Added Application Role
• [x] Updated README.md to include this PR's changes

Why

This PR is in reference to #12 which required adding application role accessibility feature.

Relevance of Application Role:

The Application role indicates to assistive technologies that this part of the web content contains elements that do not conform to any other known HTML element or WAI-ARIA widget. Any sort of special interpretation of HTML structures and widgets should be suspended, and control should be completely handed over to the browser and web application to handle mouse, keyboard, or touch interaction.

Todo:

• [x] Add Semantic Version Label
• [ ] Add tests
• [x] Add docs

[ShreyaPrasad1209]

@kendallgassner can you clarify what exactly needs to be done in "tests" in your PR template's to do list?