Old luminance coefficient in code

[gabalafou]

Comes from WCAG definition. This Stylelint rule is meant for CSS style rules, not SCSS functions, so the lint failure for this line is definitely a false positive.

However, @trallard, note:

Before May 2021 the value of 0.04045 in the definition was different (0.03928). It was taken from an older version of the specification and has been updated. It has no practical effect on the calculations in the context of these guidelines.
‐ https://www.w3.org/TR/WCAG22/#dfn-relative-luminance

Originally posted by @gabalafou in #1823 (comment)

[trallard]

So we only need to update the scss functions right?

[gabalafou]

Given the text of WCAG 2.2, I don't think we actually have to do anything, but as a matter of hygiene, aligning more closely with the spec, all that needs to be done is to swap 0.03928 with 0.04045, which I've done in #1837.