Update link in SecurityManager.md

Update link to point in and not out.

Author: Amanda Butler

docs/reference/api/connectivity/bluetooth/SecurityManager.md

@@ -12,7 +12,7 @@ Security requests may come explicitly from the user application or implicitly fr
 
 ### SecurityManager class reference
 
-[![View code](https://www.mbed.com/embed/?type=library)](http://os.mbed.com/docs/v5.7/mbed-os-api-doxy/class_security_manager.html)
+[![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/class_security_manager.html)
 
 ### SecurityManager example