refactor: evaluate values before extracting imports

[simlrh]

What kind of change does this PR introduce?
Applies postcss-modules-values before postcss-modules-extract-imports, in order to allow code such as:

@value colors: './colors.css';
.className: { composes blue from colors; }

Did you add tests for your changes?
Yes

[codecov-io]

Codecov Report

Merging #403 into master will decrease coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #403      +/-   ##
==========================================
- Coverage    98.4%   98.35%   -0.06%     
==========================================
  Files           9        9              
  Lines         314      304      -10     
  Branches       71       67       -4     
==========================================
- Hits          309      299      -10     
  Misses          5        5

Impacted Files	Coverage Δ
lib/processCss.js	97.91% <ø> (ø)	⬆️
lib/css-base.js	96.29% <0%> (-0.85%)	⬇️
lib/compile-exports.js	100% <0%> (ø)	⬆️
lib/loader.js	100% <0%> (ø)	⬆️

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[michael-ciniawsky]

@simlrh Coud you please close and reopen the PR to trigger the CLA Bot again it should work now 😛 . Would this be a breaking change under any circumstances?

[michael-ciniawsky]

@simlrh friendly ping 😛

[simlrh]

It's a breaking change in all circumstances, I believe!

Thought this was a different PR. I'm not sure about breaking things. Since you get different behaviour with this than before, it's possible someone is relying on the old behaviour.

[jsf-clabot]

All committers have signed the CLA.

[michael-ciniawsky]

@simlrh @evilebottnawi @bebraw @d3viant0ne Since we intend to remove CSS Modules from css-loader enterily in the next major and refactor them into a PostCSS Plugin used in conjunction with postcss-loader instead, this either lands as minor with the slight risk of breaking things for some users or I need to close it. Could we triage the breakage risk of this again please and make a decision upon releasing as semver minor or not ?

[alexander-akait]

/cc @michael-ciniawsky seems as breaking changes, It would be better to add a temporary option to enable this (before we drop css-modules from css-loader), but only if it frequent usage, if no maybe now be good @simlrh create branch and use own branch until we put everything in its place

[michael-ciniawsky]

Closing since we don't intend to support CSS Modules in css-loader within the next major anymore, I will consider this in cssm-loader instead. Thx 😛