fix 'gulp dev-docs' command in readme
fix 'gulp dev-docs' command in readme

haneev/react-widgets,rdjpalmer/react-widgets,thuringia/react-widgets,ksespinola/react-widgets,pvsrivathsa/react-widgets,beni55/react-widgets,jquense/react-widgets,thuringia/react-widgets,jquense/react-widgets,rickyvetter/react-widgets,pvsrivathsa/react-widgets,beni55/react-widgets,ksespinola/react-widgets,TryScratch/react-widgets,rdjpalmer/react-widgets,TryScratch/react-widgets,rickyvetter/react-widgets,haneev/react-widgets,jquense/react-widgets