change week 6 to 7

slides/bias-in-machine-learning.html

 ---
 layout: presentation
-title: AI Accessibility Bias  --Week 6--
+title: AI Accessibility Bias  --Week 7--
 description: Discussion of Bias in AI
 class: middle, center, inverse
 ---
 background-image: url(img/people.png)
 
 .left-column50[
-# Week 6: Automating Accessibility 
+# Week 7: Automating Accessibility 
 
 {{site.classnum}}, {{site.quarter}}
 ]