Merge pull request #44 from adafruit/stemma_i2c

Added commented out board.STEMMA_I2C with explanation

Author: evaherrada

examples/ds3231_simpletest.py

@@ -11,6 +11,7 @@
 import adafruit_ds3231
 
 i2c = board.I2C()  # uses board.SCL and board.SDA
+# i2c = board.STEMMA_I2C()  # For using the built-in STEMMA QT connector on a microcontroller
 rtc = adafruit_ds3231.DS3231(i2c)
 
 # Lookup table for names of days (nicer printing).