fix: upgrade multiple dependencies with Snyk

Snyk has created this PR to upgrade:
  - react from 16.13.1 to 16.14.0.
    See this package in npm: https://www.npmjs.com/package/react
  - react-dom from 16.13.1 to 16.14.0.
    See this package in npm: https://www.npmjs.com/package/react-dom

See this project in Snyk:
https://app.snyk.io/org/josdejong/project/913c7924-24ae-4f86-8a9b-91da27c3e8f1?utm_source=github&utm_medium=upgrade-pr

examples/react_demo/package.json

@@ -4,8 +4,8 @@
   "private": true,
   "dependencies": {
     "jsoneditor": "latest",
-    "react": "16.13.1",
-    "react-dom": "16.13.1",
+    "react": "16.14.0",
+    "react-dom": "16.14.0",
     "react-scripts": "3.4.1"
   },
   "scripts": {