GD extension is not a required dependency

[ossinkine]

The library successfully works without GD extension. This extension is needed if you use PngWriter to generate the QR code or if you use SvgWriter with logo option. I don't use this cases but I can't install the library until install useless GD extension. So I propose to put it to suggest section in composer.json instead of required one.

[endroid]

Hi @ossinkine thank you but I prefer to leave it in. You're correct that the extension is not strictly required as you can use other writers than the default one so I understand your question but I don't want the people who use the PNG writer (and most do) to run into errors on runtime so I prefer the somewhat too strict requirement.