Update dev dependencies

package.json

@@ -43,7 +43,7 @@
     "dev": "node ./tests/dev-server.js"
   },
   "devDependencies": {
-    "autoprefixer": "^7.1.4",
+    "autoprefixer": "^7.1.6",
     "grunt": "~1.0.1",
     "grunt-contrib-clean": "^1.1.0",
     "grunt-contrib-compress": "^1.4.3",
@@ -52,7 +52,7 @@
     "grunt-contrib-less": "^1.4.1",
     "grunt-contrib-qunit": "^2.0.0",
     "grunt-contrib-uglify": "^3.1.0",
-    "grunt-dev-update": "^2.2.0",
+    "grunt-dev-update": "^2.3.0",
     "grunt-eslint": "^20.1.0",
     "grunt-githooks": "^0.6.0",
     "grunt-postcss": "^0.9.0",
@@ -62,7 +62,7 @@
     "istanbul-instrumenter-loader": "^3.0.0",
     "postcss-clean": "^1.1.0",
     "time-grunt": "^1.4.0",
-    "webpack": "^3.6.0",
-    "webpack-dev-server": "^2.9.1"
+    "webpack": "^3.8.1",
+    "webpack-dev-server": "^2.9.4"
   }
 }