Fix typo in PICO_PORT_DIGITAL_CHANNEL enum

A missing comma in the list caused the strings
PICO_PORT_DIGITAL_CHANNEL4 and PICO_PORT_DIGITAL_CHANNEL5 to be merged.
Resulting in the enum not working properly.

Author: wsxrdv

picosdk/PicoDeviceEnums.py

@@ -78,7 +78,7 @@ def _define_channel_flags():
     "PICO_PORT_DIGITAL_CHANNEL1",
     "PICO_PORT_DIGITAL_CHANNEL2",
     "PICO_PORT_DIGITAL_CHANNEL3",
-    "PICO_PORT_DIGITAL_CHANNEL4"
+    "PICO_PORT_DIGITAL_CHANNEL4",
     "PICO_PORT_DIGITAL_CHANNEL5",
     "PICO_PORT_DIGITAL_CHANNEL6",
     "PICO_PORT_DIGITAL_CHANNEL7",