Add instagram friend lists scope

Author: Sajjad Rad

src/OAuth/OAuth2/Service/Instagram.php

@@ -21,6 +21,7 @@ class Instagram extends AbstractService
     const SCOPE_COMMENTS      = 'comments';
     const SCOPE_RELATIONSHIPS = 'relationships';
     const SCOPE_LIKES         = 'likes';
+    const SCOPE_FRIEND_LISTS    = 'follower_list';
 
     public function __construct(
         CredentialsInterface $credentials,