Fix security vulnerabilities

Upgrade @storybook/react dev package to latest version to fix a lot of
critical, severe and other security vulnerabilities.

package.json

@@ -17,7 +17,7 @@
     "storybook": "start-storybook"
   },
   "devDependencies": {
-    "@storybook/react": "^5.3.19",
+    "@storybook/react": "^6.4.13",
     "@types/connect": "^3.4.33",
     "@types/express": "^4.17.6",
     "@types/file-saver": "^2.0.1",