chore(deps-dev): bump postcss from 8.5.5 to 8.5.6

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.5 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@8.5.5...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-lock.json

@@ -55,7 +55,7 @@
     "normalize.css": "^8.0.1",
     "nunjucks": "^3.2.4",
     "open": "^10.1.2",
-    "postcss": "^8.5.5",
+    "postcss": "^8.5.6",
     "postcss-import": "^16.1.1",
     "postcss-preset-env": "^10.2.3",
     "sharp": "^0.34.2",