Switched from Bootstrap to Material UI.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "jmespath-playground",
-  "version": "1.3.1",
+  "version": "1.4.0",
   "description": "A React-based web application for testing JMESPath expressions against JSON data",
   "main": "index.js",
   "scripts": {