warmer method
Adjusts the hue of this color by amount towards
90 degrees, capping the value at 90.
If relative is true, amount will be treated as a percentage and the
hue will be adjusted by the percent of the distance from the current hue
to 90 that amount represents. If false, amount will be treated
as the number of degrees to adjust the hue by.
Implementation
@override
OklabColor warmer(num amount, {bool relative = true}) {
assert(amount > 0);
return super.warmer(amount, relative: relative).cast();
}