added support for RP2040

Author: lathoub

README.md

@@ -67,6 +67,7 @@ will create a instance named `BLEMIDI` and listens to incoming MIDI.
 ## Tested boards/modules
 - ESP32 (OOB BLE and NimBLE)
 - Arduino NANO 33 BLE
+- Arduino NANO RP2040 Connect
 
 ## Other Transport protocols:
 The libraries below  the same calling mechanism (API), making it easy to interchange the transport layer.