⬆️ Bump postcss from 8.4.21 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.21 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@8.4.21...8.4.31)

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

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

package.json

@@ -158,7 +158,7 @@
     "jest": "^29.4.2",
     "jest-environment-jsdom": "^29.4.2",
     "mini-css-extract-plugin": "^2.7.2",
-    "postcss": "^8.4.21",
+    "postcss": "^8.4.31",
     "postcss-loader": "^7.0.2",
     "prettier": "^2.8.4",
     "react-icons": "^4.8.0",