Bump postcss from 8.4.30 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.30 to 8.4.31.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.4.30...8.4.31)

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

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

package.json

@@ -140,7 +140,7 @@
     "extract-react-intl-messages": "^4.1.1",
     "husky": "^7.0.0",
     "lint-staged": "^11.0.0",
-    "postcss": "^8.4.21",
+    "postcss": "^8.4.31",
     "postcss-flexbugs-fixes": "^5.0.2",
     "postcss-import": "^15.1.0",
     "postcss-preset-env": "7.8.3",