Update default brightness

With gamma scaling, 51 is very dim, need to increase the default
brightness to be able to see the bootup animation.

Signed-off-by: Daniel Schaefer <dhs@frame.work>

Author: JohnAZoidberg

ledmatrix/src/main.rs

@@ -242,7 +242,7 @@ fn main() -> ! {
         grid: percentage(0),
         col_buffer: Grid::default(),
         animate: false,
-        brightness: 51, // Default to 51/255 = 20% brightness
+        brightness: 150,
         sleeping: SleepState::Awake,
         game: None,
         animation_period: 31_250, // 31,250 us = 32 FPS