fix: upgrade multiple dependencies with Snyk

Snyk has created this PR to upgrade:
  - react from 16.12.0 to 16.13.0.
    See this package in NPM: https://www.npmjs.com/package/react
  - react-dom from 16.12.0 to 16.13.0.
    See this package in NPM: https://www.npmjs.com/package/react-dom

See this project in Snyk:
https://app.snyk.io/org/jeremyrajan/project/fa9e3fc5-e517-4d3f-a763-e18861380247?utm_source=github&utm_medium=upgrade-pr

Author: snyk-bot

example/package-lock.json

@@ -6,8 +6,8 @@
   "private": true,
   "dependencies": {
     "prop-types": "^15.6.2",
-    "react": "^16.4.1",
-    "react-dom": "^16.4.1",
+    "react": "^16.13.0",
+    "react-dom": "^16.13.0",
     "react-scripts": "^1.1.4",
     "nice-react-ticker": "file:.."
   },