Ran black, updated to pylint 2.x

[evaherrada]

I changed this:
pins = [p for p in dir(board)]
to this:
pins = list(dir(board))
in these lines of these files:

line 139 of boardtest_simpletest.py

line 150 of boardtest_gpio.py
line 200 of boardtest_i2c.py
line 134 of boardtest_led.py
line 111 of boardtest_sd_cd.py
line 171 of boardtest_sd.py
line 247 of boardtest_spi.py
line 114 of boardtest_voltage_monitor.py
line 123 of boardtest_uart.py

let me know if that was the correct way to do that or if there is a better way. I seem to recall us coming across something similar in another PR, I just forget how it was resolved.

[kattni]

@tannewt Can you comment on the change discussed above please? You were involved in resolving the other instance of this. Thank you.

[tannewt]

This looks all good to me. I thought the output of dir() is a sequence already but this will ensure they are lists still like before.