fix(package): update react-scripts to version 3.4.0

Closes #11

Author: greenkeeper[bot]

example/package.json

@@ -6,7 +6,7 @@
     "react": "^16.3.2",
     "react-dom": "^16.3.2",
     "react-graphql-client": "^0.1.8",
-    "react-scripts": "3.1.0"
+    "react-scripts": "3.4.0"
   },
   "scripts": {
     "start": "react-scripts start",