v4.12.0

@stylable/core

• feat: flatten st-vars (#2422)

@stylable/webpack-plugin

• fix: add missing postcss dependency (#2421)

@stylable/core-test-kit

• fix: inline expects skip comments between declarations (#2414)

Infra

• run tests for integrations and core packages separately (#2380)
• add parallel flag to the test-runner (#2423)
• refactor(test-kit): remove memory-fs dependency (#2412)

Full Changelog: v4.11.0...v4.12.0