Update samples/20.a.upload-to-azure-storage/README.md

Co-Authored-By: Corina <14900841+corinagum@users.noreply.github.com>

samples/20.a.upload-to-azure-storage/README.md

@@ -77,7 +77,7 @@ You can follow our instructions on how to [setup a new Bot Channel Registration]
 1. Save the Web Chat secret to `/web/.env`
    -  `DIRECT_LINE_SECRET=a1b2c3.d4e5f6g7h8i9j0`
 
-> When you are building your production bot, never expose your Web Chat or Direct Line secret to the client. Instead, you should use the secret to generate a limited token and send it to the client. For information, please refer [to this page on how to generate a Direct Line token](https://docs.microsoft.com/en-us/azure/bot-service/rest-api/bot-framework-rest-direct-line-3-0-authentication?view=azure-bot-service-4.0#generate-token) and [Enhanced Direct Line Authentication feature](https://blog.botframework.com/2018/09/25/enhanced-direct-line-authentication-features/).
+> When you are building your production bot, never expose your Web Chat or Direct Line secret to the client. Instead, you should use the secret to generate a limited token and send it to the client. For information, please refer the documentation on [Direct Line token generation](https://docs.microsoft.com/en-us/azure/bot-service/rest-api/bot-framework-rest-direct-line-3-0-authentication?view=azure-bot-service-4.0#generate-token) and the [Enhanced Direct Line Authentication feature](https://blog.botframework.com/2018/09/25/enhanced-direct-line-authentication-features/).
 
 During development, you will run your bot locally. Azure Bot Services will send activities to your bot thru a public URL. You can use [ngrok](https://ngrok.com/) to expose your bot server on a public URL.