dht: Fix regression importing dht_readinto from pyb.

sys.platform of Pyboard is "pyboard", not "pyb".

Author: robert-hh

micropython/drivers/sensor/dht/dht.py

@@ -8,6 +8,8 @@
  from machine import dht_readinto
 elif sys.platform.startswith("esp"):
  from esp import dht_readinto
+elif sys.platform == "pyboard":
+ from pyb import dht_readinto
 else:
  dht_readinto = __import__(sys.platform).dht_readinto