Update dependency postcss-loader to v4 (main) - autoclosed

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This PR contains the following updates:

Package	Type	Update	Change
postcss-loader	dependencies	major	3.0.0 -> 4.0.0

By merging this PR, the issue #1432 will be automatically resolved and closed:

Severity	CVSS Score	CVE	Reachability
Critical	9.8	CVE-2021-44906

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Release Notes

webpack-contrib/postcss-loader (postcss-loader)

v4.0.0

Compare Source

⚠ BREAKING CHANGES

• minimum supported Node.js version is 10.13
• minimum supported webpack version is 4
• postcss was moved to peerDependencies, you need to install postcss
• PostCSS (plugins/syntax/parser/stringifier) options was moved to the postcssOptions option, please look at docs
• sourceMap default value depends on the compiler.devtool option
• the inline value was removed for the sourceMap option, please use { map: { inline: true, annotation: false } } to achieve this
• source maps contain absolute paths in sources
• loader output only CSS, so you need to use css-loader/file-loader/raw-loader to inject code inside bundle
• exec option was renamed to the execute option
• the config option doesn't support Object type anymore, config.path and config.ctx options were removed
• argument in the config for Function notation (previously config.ctx) was changed, now it contains { file, mode, webpackLoaderContext }
• loader context in the config was renamed from webpack to webpackLoaderContext

Features

• message API for emit assets (#​443) (e966ab9)
• reuse AST from other loaders (#​468) (9b75888)
• allows to use config and loader options together, options from the loader takes precedence over the config, the plugins option from the config and options are merged (0eb5aaf)
• postcssOptions options can be Function

Bug Fixes

• compatibility with webpack@5 (#​437) (ed50491)
• default export for plugins (#​465) (3d32c35)
• avoid mutations of loader options and config (#​470) (cad6f07)
• respect the map option from loader options and config (#​458) (98441ff)

Notes

• you don't need ident option for loader
• Object syntax for the plugin option is soft deprecated, please migrate on Array syntax (plugins: ['postcss-preset-env', ['cssnano', options]])

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