Fix: Update README.md => there is no longer a live demo for this sample

Author: Tom-Dynamsoft

hello-world/react/README.md

@@ -12,7 +12,6 @@ In this guide, we will be using [`dynamsoft-barcode-reader-bundle 10.2.1000`](ht
 
 ## Official Sample
 
-* <a target = "_blank" href="https://demo.dynamsoft.com/Samples/DBR/JS/hello-world/react/build/">Hello World in React - Demo</a>
 * <a target = "_blank" href="https://github.com/Dynamsoft/barcode-reader-javascript-samples/tree/main/hello-world/react">Hello World in React - Source Code</a>
 
 ## Preparation
@@ -411,4 +410,4 @@ See the section about [deployment](https://create-react-app.dev/docs/deployment/
 
 ## Support
 
-If you have any questions, feel free to [contact Dynamsoft support](https://www.dynamsoft.com/company/contact?utm_source=sampleReadme).
+If you have any questions, feel free to [contact Dynamsoft support](https://www.dynamsoft.com/company/contact?utm_source=sampleReadme).