fix(package): update react to version 16.8.3

Closes #13

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "pug": "^2.0.0-alpha6",
     "raptor-async": "^1.1.2",
     "raptor-polyfill": "^1.0.2",
-    "react": "^15.4.2",
+    "react": "^16.8.3",
     "react-dom": "^15.4.2",
     "swig": "^1.4.2",
     "uglify-js": "^3.0.0",