Update demo dependencies

Author: Oblosys

examples/parent-child-demo/package.json

@@ -8,13 +8,13 @@
   "start": "echo \"Error: This dummy package.json is only for StackBlitz deployment. Use top-level package.json instead.\" && exit 1"
   },
   "devDependencies": {
-    "react-scripts": "^3.4.4"
+    "react-scripts": "^4.0.3"
   },
   "dependencies": {
     "prop-types": "^15.7.2",
-    "react": "^17.0.1",
-    "react-dom": "^17.0.1",
+    "react": "^17.0.2",
+    "react-dom": "^17.0.2",
     "react-hot-loader": "^4.13.0",
-    "react-lifecycle-visualizer": "2.2.11"
+    "react-lifecycle-visualizer": "2.2.12"
   }
 }