chore(deps-dev): bump postcss from 8.5.4 to 8.5.6

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.4 to 8.5.6.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.4...8.5.6)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.6
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package.json

@@ -55,7 +55,7 @@
     "eslint-plugin-simple-import-sort": "12.1.1",
     "jest": "30.0.3",
     "markdownlint-cli": "0.45.0",
-    "postcss": "8.5.4",
+    "postcss": "8.5.6",
     "prettier": "3.5.3",
     "tailwindcss": "3.4.14",
     "typescript": "5.8.3"