Update dependencies, add webpack-cli

Finish when webpack/webpack-cli#478 is released

Gemfile.lock

@@ -56,7 +56,7 @@ GEM
     archive-zip (0.11.0)
       io-like (~> 0.3.0)
     arel (9.0.0)
-    autoprefixer-rails (8.5.2)
+    autoprefixer-rails (8.6.0)
       execjs
     babel-source (5.8.35)
     babel-transpiler (0.7.0)

package.json

@@ -1,19 +1,20 @@
 {
   "dependencies": {
-    "@rails/webpacker": "^3.0.1",
-    "autoprefixer": "^8.1.0",
+    "@rails/webpacker": "^3.5.3",
+    "autoprefixer": "^8.6.0",
     "axios": "^0.18.0",
     "babel-preset-react": "^6.24.1",
     "libsodium-wrappers-sumo": "^0.7.2",
     "promise-queue": "^2.2.3",
     "prop-types": "^15.6.0",
     "qrcode": "^1.0.0",
-    "react": "^16.0.0",
-    "react-dom": "^16.0.0",
+    "react": "^16.4.0",
+    "react-dom": "^16.4.0",
     "react-lazyload": "^2.3.0",
     "react-scroll-up": "^1.3.3",
     "react_ujs": "^2.2.0",
-    "webpack-dev-server": "^3.1.1"
+    "webpack-cli": "^3.0.0",
+    "webpack-dev-server": "^3.1.4"
   },
   "devDependencies": {
     "webpack-bundle-analyzer": "^2.9.0"