Function goldenAngleColour

goldenAngleColour(
    index: number,
    saturation?: number,
    lightness?: number,
    alpha?: number,
): string
Returns a full HSL colour string (eg hsl(20,50%,75%)) based on a index. It's useful for generating perceptually different shades as the index increments.
```
el.style.backgroundColor = goldenAgeColour(10);
```
Saturation and lightness can be specified, as numeric ranges of 0-1.
Parameters
- index: number
- saturation: number = 0.5
  Saturation (0-1), defaults to 0.5
- lightness: number = 0.75
  Lightness (0-1), defaults to 0.75
- alpha: number = 1
  Opacity (0-1), defaults to 1.0
Returns string
HSL colour string eg hsl(20,50%,75%)