Update react to the latest version 🚀 (#975)

* chore(package): update react to version 16.8.0

* chore(package): update react-dom to version 16.8.0

* chore(package): update react-test-renderer to version 16.8.0

* chore(package): update lockfile package-lock.json

Author: greenkeeper[bot]

package-lock.json

@@ -77,13 +77,13 @@
     "prismjs": "1.15.0",
     "prop-types": "15.6.2",
     "query-string": "6.1.0",
-    "react": "16.4.1",
+    "react": "16.8.0",
     "react-dnd": "5.0.0",
     "react-dnd-html5-backend": "5.0.1",
-    "react-dom": "16.4.1",
+    "react-dom": "16.8.0",
     "react-router": "4.3.1",
     "react-router-dom": "4.3.1",
-    "react-test-renderer": "16.4.1",
+    "react-test-renderer": "16.8.0",
     "request": "2.87.0",
     "request-promise": "4.2.2",
     "sass-loader": "7.1.0",