chore(deps-dev): bump postcss from 8.4.14 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.14 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@8.4.14...8.4.31)

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

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

package.json

@@ -98,7 +98,7 @@
     "eslint-plugin-prettier": "^3.1.3",
     "eslint-plugin-react": "^7.19.0",
     "husky": "^4.3.5",
-    "postcss": "^8.4.14",
+    "postcss": "^8.4.31",
     "prettier": "2.0.5",
     "pretty-quick": "^3.1.0",
     "react-inspector": "^3.0.2"