Update cgltf to add support for webp textures in gltf/glb scenes

[hannojg]

Is your feature request related to a problem? Please describe.

Use webp for textures in gltf/glb scenes. Webp is usually better compressed than e.g. jpeg and I'd really like it on mobile to optimise the size of my scenes.

Describe the solution you'd like

In a recent PR cgltf added support for webp:

• Implement support for EXT_texture_webp jkuhlmann/cgltf#253

I think all we'd need to do in filament is update cgltf and maybe add some small changes to filament to make it work?

Describe alternatives you've considered

/

OS and backend

its not, I think cgltf is used cross platform.

[hannojg]

Note: I just realised that since the mentioned PR get merged no new release has been created. So we have to wait for a bit…