Fix broken starter url

Author: sidharthachatterjee

docs/starters.yml

@@ -2414,7 +2414,7 @@
     - 📣 react-axe for console reporting of accessibility errors in the DOM during development
     - 📖 storybook setup for accessibility reporting on individual components
 - url: https://gatsby-theme-ggt-material-ui-blog.netlify.com/
-  repo: https://github.com/greatgatsbyjsthemes/gatsby-starter-ggt-material-ui-blog
+  repo: https://github.com/avatar-kaleb/gatsby-starter-ggt-material-ui-blog
   description: Starter material-ui blog utilizing a Gatsby theme!
   tags:
     - Blog