Allow override of $color-mappings

[LokiMidgard]

Similar how $breakpoints are overridden, it would be nice to override $color-mappings.

Somthing like:

@use "@picocss/pico/scss/pico.scss" with (
    $theme-color: "myTheme",
    $color-mappings: ("myTheme": 
        ("dark": 
            ("text-selection-color": rgba($amber-350, 0.1875),
                "primary": $amber-350,
                "primary-background": $amber-200,
                "primary-underline": rgba($amber-350, 0.5),
                "primary-hover": $amber-250,
                "primary-hover-background": $amber-150,
                "primary-focus": rgba($amber-350, 0.375),
                "primary-inverse": $black,
                "switch-thumb-box-shadow": 0 0 0.5rem rgba($black, 0.25),
            ),
            "light": ("text-selection-color": rgba($amber-400, 0.25),
                "primary": $amber-550,
                "primary-background": $amber-200,
                "primary-underline": rgba($amber-550, 0.5),
                "primary-hover": $amber-650,
                "primary-hover-background": $amber-250,
                "primary-focus": rgba($amber-400, 0.5),
                "primary-inverse": $black,
                "switch-thumb-box-shadow": 0 0 0.5rem rgba($black, 0.25),
            ),
        )));

this would seem to be easier then overriding the css-variables and reimplement when which theme is used.

I'm have not much experience with sass, but I assume this is possible?