Couple tweaks to RGB LED

[sorgelig]

According to datasheet, RGB LED has 32 levels of brightness unrelated to RGB value, so i've modified the code:

TinyPICO::TinyPICO()
{
    ...
    brightness = 15;
    ...
}

void TinyPICO::DotStar_SetBrightness(uint8_t b)
{
    if(b>31) b = 31;
    brightness = b;
}

void TinyPICO::DotStar_Show(void)
{
    if ( !isInit )
    {
        isInit = true;
        swspi_init();
        delay(10);
    }
    
    // Start-frame marker
    for( int i=0; i<4; i++) swspi_out(0x00);    
    
    // Pixel start + brightness
    swspi_out(0xE0 | brightness);     
    
    for( int i=0; i<3; i++) swspi_out(pixel[i]); // R,G,B @Full brightness (no scaling) 

    // // End frame marker
    swspi_out(0xFF);  
}

It works fine and RGB values aren't loosing precision. I don't know your original intention for manual brightness, so didn't want to make a pull request.

Another tweak i think is useful is to remove delay(1) from the end of swspi_out. LED works fine without delay but presence of it may be crucial for time sensitive tasks in main loop (like in my case).