message: updated example to use github/primer pairing
diff: @@ -14,8 +14,8 @@ Avatars are images used to represent users and organizations on GitHub. They typ
  To create a Parent + Child avatar combination, wrap Avatars in AvatarPair:
  ```jsx live
  <AvatarPair my={4}>
  + <Avatar src="https://avatars.githubusercontent.com/github"/>
  <Avatar src="https://avatars.githubusercontent.com/primer"/>
  - <Avatar src="https://avatars.githubusercontent.com/emplums"/>
  </AvatarPair>
  ```
  