Bump postcss from 8.4.28 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.28 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@8.4.28...8.4.31)

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

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

Author: dependabot[bot]

examples/react/package.json

@@ -25,7 +25,7 @@
     "@vitejs/plugin-react": "^3.1.0",
     "autoprefixer": "^10.4.13",
     "concurrently": "^7.6.0",
-    "postcss": "^8.4.21",
+    "postcss": "^8.4.31",
     "tailwindcss": "^3.2.7",
     "typescript": "^4.9.3",
     "vite": "^4.1.0"

examples/svelte/package.json

@@ -28,7 +28,7 @@
 		"eslint": "^8.28.0",
 		"eslint-config-prettier": "^8.5.0",
 		"eslint-plugin-svelte3": "^4.0.0",
-		"postcss": "^8.4.21",
+		"postcss": "^8.4.31",
 		"prettier": "^2.8.0",
 		"prettier-plugin-svelte": "^2.8.1",
 		"svelte": "^3.54.0",