Update slider

[caternuson]

Removes a left over serial print, but also changes the actual slider logic. With rounding to first decimal place there was a jump from 0.2 to 0.4 and 0.6 to 0.8. The slider has 9 possible "positions", which leads to increments of 1/8th:

1 0.000
2 0.125
3 0.250
4 0.375
5 0.500
6 0.625
7 0.750
8 0.875
9 1.000

So, instead of rounding, return the slider value with 1/8th increments.

Test code:

import time
from adafruit_funhouse import FunHouse

fh = FunHouse()

while True:
    s = fh.peripherals.slider
    if s is not None:
        print(s)
        time.sleep(0.1)

Output:

Adafruit CircuitPython 6.2.0 on 2021-04-05; Adafruit FunHome with ESP32S2
>>> import test_slider
1.0
1.0
1.0
0.875
0.75
0.625
0.625
0.625
0.5
0.5
0.375
0.375
0.375
0.25
0.25
0.25
0.125
0.125
0.125
0.125
0.0
0.0
0.0

[makermelissa]

Looks good, thanks.