Php file (/src/Curl/Curl.php) has an error

The file(src/Curl/Curl.php) has an error on line 1073:

Code:
```php
$this-setOpt(CURLOPT_PROXYAUTH, $auth);
```
changes Code:
```php
$this->setOpt(CURLOPT_PROXYAUTH, $auth);
```
