chore(deps-dev): bump postcss from 8.4.16 to 8.4.31 in /ui

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.16 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@8.4.16...8.4.31)

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

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

Author: dependabot[bot]

ui/packages/ce/package.json

@@ -83,7 +83,7 @@
     "cspell": "^5.12.6",
     "eslint": "^8.2.0",
     "monaco-editor": ">=0.25.0 <1.0.0",
-    "postcss": "^8.3.3",
+    "postcss": "^8.4.31",
     "prettier": "^2.4.1",
     "sass": "^1.43.2",
     "stylelint": "^14.0.1",