Renovate[bot]: Update dependency postcss to v8.4.31

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
postcss (source)	8.4.30 -> 8.4.31

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Pre-merge checks

• [x] Make sure the GitHub Actions tests are passing.

• [x] Run bin/compare-build-branch.sh locally on this branch and confirm that this PR is not causing unexpected changes to the build. Requirements to run this script: grunt build and nvm.

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Release Notes

postcss/postcss (postcss)

### [`v8.4.31`](https://togithub.com/postcss/postcss/blob/HEAD/CHANGELOG.md#8431) [Compare Source](https://togithub.com/postcss/postcss/compare/8.4.30...8.4.31) - Fixed `\r` parsing to fix CVE-2023-44270.

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Configuration

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

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This PR has been generated by Mend Renovate. View repository job log here.

[mattyrob]

Local run of bin/compare-build-branch.sh renovate/postcss-8.x returned:

Diff results for branch: renovate/postcss-8.x
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       0 build-compare.diff