chore(deps): update dependency postcss to v8.4.28

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
postcss (source)	8.4.27 -> 8.4.28

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Release Notes

postcss/postcss (postcss)

### [`v8.4.28`](https://togithub.com/postcss/postcss/blob/HEAD/CHANGELOG.md#8428) [Compare Source](https://togithub.com/postcss/postcss/compare/8.4.27...8.4.28) - Fixed `Root.source.end` for better source map (by Romain Menke). - Fixed `Result.root` types when `process()` has no parser.

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Configuration

📅 Schedule: Branch creation - "every weekend" in timezone Asia/Singapore, Automerge - At any time (no schedule defined).

🚦 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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• [ ] If you want to rebase/retry this PR, check this box

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[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (e6b3a7c) 53.44% compared to head (7fb552f) 53.44%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #3610 +/- ## ======================================= Coverage 53.44% 53.44% ======================================= Files 271 271 Lines 5862 5862 Branches 1396 1396 ======================================= Hits 3133 3133 Misses 2729 2729 ```

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