Windows: Update list_port_windows.py to latest chinaheyu:pyserial

This fixes empty name fields in the Windows serial port list.

Fixes #549
Refs pyserial/pyserial#725

Author: UnionSystems

src/greaseweazle/tools/list_ports_windows.py

@@ -1317,6 +1317,10 @@ def iterate_comports(cache_usb_info=True):
             continue
         yielded_devices.append(port_device)
 
+        # Skip ports with empty names (Thanks keirf/greaseweazle#550).
+        if port_device.port_name is None:
+            continue
+
         # Skip parallel ports.
         if port_device.port_name.startswith('LPT'):
             continue