chore(package): update autoprefixer to version 7.1.0

Closes #345

Author: greenkeeper[bot]

package.json

@@ -23,7 +23,7 @@
     "react-dom": "^15"
   },
   "devDependencies": {
-    "autoprefixer": "6.7.7",
+    "autoprefixer": "7.1.0",
     "babel-core": "^6.23.1",
     "babel-eslint": "^7.1.1",
     "babel-loader": "^7.0.0",