Example error

The example in the documentation:
```
import st7789_base, st7789_ext
from machine import Pin

display = st7789_ext.ST7789(
SPI(1, baudrate=40000000, phase=0, polarity=0),
160, 128,
reset=machine.Pin(2, machine.Pin.OUT),
dc=machine.Pin(4, machine.Pin.OUT),
cs=machine.Pin(10, machine.Pin.OUT),
inversion = False,
)
```
This causes the following error:
```
MPY: soft reboot
Traceback (most recent call last):
File "", line 70, in
TypeError: unexpected keyword argument 'inversion'
```
Looks like 'inversion' is no longer included in the initialization parameters. There are references to 'inversion' settings in the module. Worked without the parameter.

Curt