Add lightness-notation

[ybiquitous]

Which issue, if any, is this issue related to?

Ref stylelint/stylelint#7366

Is there anything in the PR that needs further explanation?

Stylelint 16.1.0 will add a new rule lightness-notation.

I believe specifying the "percentage" primary option makes sense since percentage lightness values are often used. For example, see the MDN document about oklch().

For example:

$ echo 'a { color: oklch(0.85 0.17 88deg) }' | npx stylelint -c index.js

<input css 1A2DBa>
 1:18  ✖  Expected "0.85" to be "85%"  lightness-notation

1 problem (1 error, 0 warnings)

[jeddy3]

LGTM to merge as part of the release process.