Update basic-usage.md

[PrabalPradhan1991]

Adds a section "Selecting a driver"

Selecting a driver

By default, the Imagick driver will be used. However if you would like to use GD you can do this by selecting the driver before loading the image.

use Spatie\Image\Image;

$image = Image::load($file)->useImageDriver('imagick'); // for imagick
$image = Image::load($file)->useImageDriver('gd'); // for gd

[freekmurze]

Thanks!