Update pattern status link in README.md

[geppy]

The wiki's Design Pattern Status page was renamed earlier this year.
This PR updates the README's link to that wiki page.

[mcking65]

Thanks @geppy , appreciate it.

This is actually a reminder that I need to updated the readme ... the directions in that section are not very helpful.

[geppy]

@mcking65 You're very welcome! I've fixed bugs in some of the examples, should I wait to see the updated instructions?

The wiki instructions may also need attention, but evidently you can't do PRs for wikis. I noticed they still say to use JSCS.

[mcking65]

To contribute to the deliverables, before changing code and submitting a PR, the best thing to do is either comment in an existing issue or raise a new issue to discuss the bug and the nature of the fix. This will also help avoid conflicts with other people who may be working on the same example or section of the document.

To see what is at the top of our priority list, the best thing is to checkout the milestone plan. We are currently working on the release 1 milestone.
https://github.com/w3c/aria-practices/milestones

A good number of the patterns and examples have projects associated with them where you can see next steps and what is in progress:
https://github.com/w3c/aria-practices/projects