Bump postcss from 8.5.6 to 8.5.8 (#3387)

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.6 to 8.5.8.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.6...8.5.8)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.8
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package.json

@@ -37,7 +37,7 @@
     "concurrently": "^9.2.1",
     "del": "^7.1.0",
     "eslint": "^9.39.3",
-    "postcss": "^8.5.6",
+    "postcss": "^8.5.8",
     "prettier": "3.8.1",
     "prettier-plugin-astro": "^0.14.1",
     "release-plan": "^0.17.4",