Update helloworld-pwa.html

Author: aloksha

1.hello-world/10.read-video-pwa/helloworld-pwa.html

@@ -7,6 +7,7 @@
     <meta name="description" content="Read barcodes from camera with Dynamsoft Barcode Reader in a PWA application.">
     <meta name="keywords" content="read barcode from camera in PWA">
     <title>Dynamsoft Barcode Reader PWA Sample - Hello World (Decoding via Camera)</title>
+    <link rel="canonical" href="https://demo.dynamsoft.com/Samples/DBR/JS/1.hello-world/10.read-video-pwa/helloworld-pwa.html">
     <link rel="manifest" href="./helloworld-pwa.json">
 </head>