build(deps-dev): bump postcss from 8.4.29 to 8.4.31 in /web

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.29 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@8.4.29...8.4.31)

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

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

web/package.json

@@ -28,7 +28,7 @@
 		"eslint": "^8.28.0",
 		"eslint-config-prettier": "^9.0.0",
 		"eslint-plugin-svelte": "^2.30.0",
-		"postcss": "8.4.29",
+		"postcss": "8.4.31",
 		"prettier": "^3.0.3",
 		"prettier-plugin-svelte": "^3.0.3",
 		"svelte": "^4.0.5",