[Feature] Allow floating point brightness value in light array

[laurensvalk]

Is your feature request related to a problem? Please describe.

>>> a = UltrasonicSensor(Port.F)
>>> a.lights.on(50)
>>> a.lights.on(50/2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: object 'float' isn't a tuple or list

Describe the solution you'd like
Allow floating point value, truncated to int, as we do everywhere else.