fix third parameter on Github\Api\PullRequest::list call

                   
|Q            |A  |
|---          |---|
|Bug Fix?     |y  |
|New Feature? |n  |
|BC Breaks?   |n  |
|Deprecations?|n  |
|Tests Pass?  |n  |
|Fixed Tickets|   |
|License      |MIT|
|Doc PR       |   |
                   


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As state is only used as the parameter I rather move it there.

```
$fetchedPrs = $api->all(
   $this->getUsername(),
   $this->getRepository(),
   ['state' => $state]
);
```