Override default color palettes/ color families

[karneaud]

Describe the issue

Cannot add or override color palette to generate custom color/background color classes in sass

Current Behavior

when overriding the color-families with a custom palette with colors, background-colors set to true the classes are not generated. I can't seem to override/ extend the colors.$colors that mixins use to generate classes

@use '@picocss/pico/scss/colors/utilities/colors' as pico-colors with (
    $colors: brand.$colors
); 
@use '@picocss/pico/scss/colors/utilities/background-colors' as pico-background with (
    $colors: brand.$colors
);

Expected Behavior

We should at least be able to override the default color palette without having to duplicate our own version of mixins