Possible fix for avatars showing stale image data

By giving React a different key for different users' avatars, this hopefully ensures that a new <img> element will be created when the avatar component switches to a different user.

src/Avatar.tsx

@@ -136,6 +136,7 @@ export const Avatar: FC<Props> = ({
 
   return (
     <CompoundAvatar
+      key={id}
       className={className}
       id={id}
       name={name}