chore(deps): update dependency postcss to v8.4.39

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
postcss (source)	8.4.38 -> 8.4.39

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Release Notes

postcss/postcss (postcss)

### [`v8.4.39`](https://togithub.com/postcss/postcss/blob/HEAD/CHANGELOG.md#8439) [Compare Source](https://togithub.com/postcss/postcss/compare/8.4.38...8.4.39) - Fixed `CssSyntaxError` types (by [@​romainmenke](https://togithub.com/romainmenke)).

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Configuration

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🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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[bundlemon[bot]]

BundleMon (elements)

Unchanged files (3)

Status | Path | Size | Limits :------------: | ------------ | :------------: | :------------: :white_check_mark: | index.js
| 266.04KB | - :white_check_mark: | mutation-test-elements.js
| 196.32KB | - :white_check_mark: | index.cjs
| 196.32KB | -

No change in files bundle size

Final result: :white_check_mark:

View report in BundleMon website ➡️

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Current branch size history | Target branch size history