Bump postcss from 8.4.26 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.26 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@8.4.26...8.4.31)

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

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

package.json

@@ -44,7 +44,7 @@
     "jquery": "^3.7.1",
     "npm-run-all": "^4.1.5",
     "popper.js": "^1.16.1",
-    "postcss": "^8.4.26",
+    "postcss": "^8.4.31",
     "postcss-cli": "^10.1.0",
     "prettier": "^3.0.3",
     "stylelint": "^15.10.1",