Need support for `@value` declarations

[SkReD]

Problem

Css modules variables values not converted by color function

Example

// index.css
@value transparentBlack: color(#333 a(8%));

//index.js
@import { transparentBlack } from './index.css';

console.log(transparentBlack) 

Intended outcome

rgba(51, 51, 51, 0.36)

Actual outcome

color(#333 a(8%))

[SkReD]

Add pull request https://github.com/postcss/postcss-color-function/pull/51