Update composer.json

Set philf/setting to dev-master, according to: https://packagist.org/packages/philf/setting

> Problem 1
>    - Installation request for anahkiasen/flatten dev-master -> satisfiable by anahkiasen/flatten[dev-master].
>    - anahkiasen/flatten dev-master requires philf/setting dev-develop -> no matching package found.