Add posthtml-style-expansion

[renyamizuno]

Notable Changes

Add posthtml-style-expansion to CSS plugins.

Commit Message Summary (CHANGELOG)

Add posthtml-style-expansion

Type

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• CI
• Fix
• Perf
• Docs
• Test
• Chore
• Style
• Build
• Feature
• Refactor

SemVer

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• Fix (:label: Patch)
• Feature (:label: Minor)
• Breaking Change (:label: Major)

Issues

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noop.

Checklist

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• Lint and unit tests pass with my changes
• I have added tests that prove my fix is effective/works
• I have added necessary documentation (if appropriate)
• Any dependent changes are merged and published in downstream modules

[coveralls]

Coverage remained the same at 100.0% when pulling c0d874c on renyamizuno:patch-1 into e951b9f on posthtml:master.

[Scrum]

@renyamizuno thanks!