Update README.md

Author: turbinenreiter

README.md

@@ -27,7 +27,7 @@ Example:
 ```python
 from bmp180 import BMP180
 from machine import I2C, Pin                        # create an I2C bus object accordingly to the port you are using
-bus = I2C(1, I2C.MASTER, baudrate=100000)           # on pyboard
+bus = I2C(1, baudrate=100000)           # on pyboard
 # bus =  I2C(scl=Pin(4), sda=Pin(5), freq=100000)   # on esp8266
 bmp180 = BMP180(bus)
 bmp180.oversample_sett = 2