A new constant for raspberry pi 3b +

Added a new revision of raspberry pi 3b + to constants

Author: kaangoksal

adafruit_platformdetect/constants/boards.py

@@ -504,7 +504,7 @@
         "2a32082",
         "2a52082",  # warranty bit 25
     ),
-    RASPBERRY_PI_3B_PLUS: ("a020d3", "1a020d3", "2a020d3"),  # warranty bits
+    RASPBERRY_PI_3B_PLUS: ("a020d3", "1a020d3", "2a020d3", "a020d4"),  # warranty bits
     RASPBERRY_PI_AVNET_IIOT_GW: ("60a220b0",),
     RASPBERRY_PI_CM3: (
         "a020a0",