Explicitly require Mink Goutte driver >=1.0.9

This PR somehow fixes #63, summarised below. It is unclear whether this is a Composer bug or intended behaviour.

---

As it stands, the QA tools don't install with a default Symfony2 SE installation on PHP 5.5.9.

To reproduce:

```sh-session
$ composer create-project symfony/framework-standard-edition sf2qa \~2 -n
$ cd sf2qa
$ composer require --dev ibuildings/qa-tools:1.1.26
```