ACT Framework Req update

Hey team,

I've updated the requirements document based on the feedback from last this
week's call. You can find the current PR here:
https://github.com/w3c/wcag-act/pull/1/files

Please review the changes and leave any comments before the end of Tuesday.
In particular, take a look at the user stories we developed before:
https://www.w3.org/WAI/GL/task-forces/conformance-testing/wiki/User_stories

-- 
*Wilco Fiers* - Senior Accessibility Engineer