Update gltf validator to 2.0.0-dev.2.7
Update gltf validator to 2.0.0-dev.2.7

jbousquie/Babylon.js,Kesshi/Babylon.js,BabylonJS/Babylon.js,NicolasBuecher/Babylon.js,NicolasBuecher/Babylon.js,sebavan/Babylon.js,NicolasBuecher/Babylon.js,Kesshi/Babylon.js,BabylonJS/Babylon.js,RaananW/Babylon.js,sebavan/Babylon.js,RaananW/Babylon.js,BabylonJS/Babylon.js,RaananW/Babylon.js,Kesshi/Babylon.js,jbousquie/Babylon.js,sebavan/Babylon.js,jbousquie/Babylon.js