Update README.md

Author: leonardocavagnis

README.md

@@ -2,7 +2,9 @@
 
 > [!WARNING]
 > This library is deprecated and no longer actively maintained.
-> We recommend transitioning to the [Arduino_PortentaMachineControl](https://github.com/arduino-libraries/Arduino_PortentaMachineControl) library for ongoing support, new features and contributions.
+>
+> We recommend transitioning to the [Arduino_PortentaMachineControl](https://github.com/arduino-libraries/Arduino_PortentaMachineControl) library for ongoing support, new features and contributions. If you need assistance with migration, refer to the [migration guide](https://docs.arduino.cc/tutorials/portenta-machine-control/pmc-arduino-library).
+>
 > Please note that the [examples](./examples/) provided with this library are not compatible with the new library.
 
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