fix(package): update react-scripts to version 3.3.1

Closes #25

Author: greenkeeper[bot]

package.json

@@ -13,7 +13,7 @@
     "react-dom": "^16.2.0",
     "react-emotion": "^9.1.3",
     "react-final-form": "^3.1.0",
-    "react-scripts": "1.1.3"
+    "react-scripts": "3.3.1"
   },
   "scripts": {
     "start": "react-scripts start",