chore(deps): bump postcss from 8.4.20 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.20 to 8.4.31.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.20...8.4.31)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:production
...

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

internals/stylelint-config/package.json

@@ -44,7 +44,7 @@
     "stylelint": "^14.13.0"
   },
   "dependencies": {
-    "postcss": "^8.4.20",
+    "postcss": "^8.4.31",
     "postcss-html": "^1.5.0",
     "postcss-scss": "4.0.6",
     "stylelint-config-prettier": "^9.0.4",