fix(package): update react to version 16.5.0

Closes #43

Author: greenkeeper[bot]

package.json

@@ -46,7 +46,7 @@
     "postcss-advanced-variables": "1.2.2",
     "postcss-loader": "1.1.0",
     "prettyjson": "1.1.3",
-    "react": "^15.3.2",
+    "react": "^16.5.0",
     "react-codemirror": "0.2.6",
     "react-dom": "^15.3.2",
     "react-transform-catch-errors": "1.0.2",