Add brightness getter/setter.

[CedarGroveStudios]

Add a property to read and set NeoPixel array brightness levels for both the single NeoTrellis board driver neotrellis.py and the multiple-board driver multitrellis.py. Also updated the two examples to include use of the new property.

# Set the brightness value (0 to 1.0)
trellis.brightness = 0.5

The brightness property is passed to the underlying neopixel driver class where brightness values in the range of 0.0 to 1.0 are verified.

Tested on an 8x8 NeoTrellis device consisting of four 4x4 NeoTrellis boards and a Feather M4 Express running CircuitPython 7.3.0.

Adafruit CircuitPython 7.3.0 on 2022-05-23; Adafruit Feather M4 Express with samd51j19

[ladyada]

didnt test with hardware however seems ok!
@jedgarpark may want to test this as well when back from vacation

[jedgarpark]

Nice, I was just doing multi-trellis stuff and can use this. I’ll test when I’m back next week.

[jedgarpark]

I just tested it on the NeoTrellis 8x8 and it works beautifully! Thanks, this makes it much easier to pick colors and deal with brightness separately.

[CedarGroveStudios]

Thank you, John!

[CedarGroveStudios]

@ladyada Please let me know if there's anything I can do to help move this forward towards the merge.

[jepler]

@CedarGroveStudios it looks like there's a file that needs a conflict resolved. Are you familiar with this process, or would you like a hand?

[CedarGroveStudios]

@CedarGroveStudios it looks like there's a file that needs a conflict resolved. Are you familiar with this process, or would you like a hand?

@jepler Thanks for your offer to help. I’ll see if I can fix it myself. I only submit a couple of PRs in a year, so it takes me a while to relearn and discover all the new environment changes.

[CedarGroveStudios]

Resolved, retested on the 8x8 NeoTrellis, and resubmitted. Should be good to go.

[jepler]

Thank you! Merging based on JP's earlier review