previous solution
// change gp color palette
add_filter( 'generate_default_color_palettes', 'tu_custom_color_palettes' );
function tu_custom_color_palettes( $palettes ) {
$palettes = array(
'#351C4D', /* brand */
'#FEBF7B', /* accent */
'#FF7E5F', /* action */
'#765285', /* hover */
'#C1c1c1', /* light */
'#fe7b84', /* midtone */
'#000000', /* black */
'#FFFFFF', /* white */
);
return $palettes;
}