[amazondashbutton] Update README.md (#8958)

Information about how to use Dash Buttons nowadays as Amazon doesn't support them anymore.

Also-by: Wouter Born <github@maindrain.net>
Signed-off-by: Marcel Simat <marcel@freese.name>

bundles/org.openhab.binding.amazondashbutton/README.md

@@ -75,9 +75,9 @@ A few known operating systems are:
 
 ## Setup Dash Button
 
-Setting up your Dash Button is as simple as following the instructions provided by [Amazon](https://www.amazon.com/Dash-Buttons/b?node=10667898011) **EXCEPT FOR THE LAST STEP**.
-Follow the instructions to set up the Dash Button in their mobile app.
-When you get to the step where it asks you to pick which product you want to map it to, just quit the setup process.
+Amazon itself doesn't support Dash Buttons anymore.
+Instructions how to use them without having to rely on Amazon's servers can be found at https://blog.christophermullins.com/2019/12/20/rescue-your-amazon-dash-buttons/ - at least for some firmware versions.
+Take care to block internet access for the button or it will be bricked.
 
 {: #no-phonehome}
 ## Preventing Communication with Amazon Servers