Image format webp is not preserve transparent

[amigoscs]

Image format webp is not preserve transparent during resize.

I found the problem in the code /system/Images/Handlers/GDHandler.php

`
Line 249

...
if ($this->image()->imageType === IMAGETYPE_PNG) // png we can actually preserve transparency
{
imagealphablending($dest, false);
imagesavealpha($dest, true);
}
...
`

fixing the code on this one solves the problem

... if ($this->image()->imageType === IMAGETYPE_PNG || $this->image()->imageType === IMAGETYPE_WEBP) ...

Please keep this issue in mind in future releases. Thanks!