hsl & hsla color formats not supported

[petrkotek]

Would be nice to add a support for HSL and HSLA:

hsl(hue, saturation, lightness)
hsla(hue, saturation, lightness, alpha)

Examples:

hsl(120, 50%, 50%)
hsla(120, 50%, 50%, 0.5)

This would be implemented in parseColor method:

SVG-to-PDFKit/source.js

Line 471 in b091ebd

function parseColor(raw) {

(Note: I should be able to implement this in the next few days.)