add missing autoprefixer dev dependency
add missing autoprefixer dev dependency

Signed-off-by: Sébastien Gruhier <39b7937d05257c715184300ec3ebabb04d12e735@xilinus.com>

gravity-addiction/angular2-webpack-login,carluccyo/reese-admin,preboot/angular-webpack,tux2323/angular2-webpack,kattsushi/electron-angular2-seed,Selleo/angular2-workshop,carluccyo/reese-admin,jojanper/angular-app,Foxandxss/angular2-webpack,prohorova/angular2-map-component,Selleo/angular2-workshop,Cammisuli/angular2-animation-test,aismwise/hackers-toolkit,headfwd/mrbox-front-end,CovalentLabs/project-w-app,gravity-addiction/angular2-webpack-login,tux2323/angular2-webpack,aitor-garcia-p/webgira-showcase,lodybo/testing-in-angular,Zinadore/capstoneed-common,lodybo/testing-in-angular,Znow/ZnowBlog,CovalentLabs/project-w-app,Foxandxss/angular2-webpack,Zinadore/capstoneed-common,Znow/ZnowBlog,onelazyugy/angular2-webpack,rborgwald/recipe-ui,onelazyugy/angular2-webpack,stardom84/clinics,gravity-addiction/angular2-webpack-login,jojanper/angular-app,prohorova/angular2-map-component,Selleo/angular2-workshop,leviathan88/furkan,internetjesus/ng2-dd,flosky/fashioncloud-angular2-hackathon,aitor-garcia-p/webgira-showcase,rborgwald/recipe-ui,internetjesus/ng2-dd,preboot/angular2-webpack,leviathan88/furkan,Zinadore/capstoneed-common,jgiunti/angular2-webpack-bootsrapv4-starter,kattsushi/electron-angular2-seed,stardom84/clinics,internetjesus/ng2-dd,Foxandxss/angular2-webpack,jojanper/angular-app,aitor-garcia-p/webgira-showcase,leviathan88/furkan,Znow/ZnowBlog,stardom84/clinics,preboot/angular-webpack,Cammisuli/angular2-animation-test,jgiunti/angular2-webpack-bootsrapv4-starter,preboot/angular2-webpack,flosky/fashioncloud-angular2-hackathon,aismwise/hackers-toolkit,rborgwald/recipe-ui,lodybo/testing-in-angular,prohorova/angular2-map-component,onelazyugy/angular2-webpack,prohorova/angular2-map-component,kattsushi/electron-angular2-seed,preboot/angular-webpack,headfwd/mrbox-front-end,CovalentLabs/project-w-app,rborgwald/recipe-ui,tux2323/angular2-webpack,flosky/fashioncloud-angular2-hackathon,jgiunti/angular2-webpack-bootsrapv4-starter,Cammisuli/angular2-animation-test,preboot/angular2-webpack,headfwd/mrbox-front-end,carluccyo/reese-admin,aismwise/hackers-toolkit