CSS Colors version 3.0

[mrtnzlml]

I am currently a bit busy to start working on this but I would like to outline here how should the @adeira/css-colors package evolve for the future 3.0 major version. Basically, the main goal of this release should be to get rid of the [R, G, B] triplet and replace it with some better structure that includes an alpha channel as well.

Public interface changes:

• calculateContrastRatio should accept the new structure instead of RGB triplets
• isAccessible should accept the new structure instead of RGB triplets
• chooseHigherContrast should accept the new structure instead of RGB triplets (also please note this comment: Colors: add new function chooseHigherContrast #2741 (review))
• remove deprecated isDark (e7f1673)
• remove deprecated isBright (e7f1673)
• remove convertToRGBTriplet (doesn't make sense anymore with the new structure)

Unchanged functions:

• cssColorNames, isColor, normalizeColor, hex3ToHex6, hex6ToHex3

Inspiration: https://github.com/d3/d3-color