Bump postcss from 8.4.20 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.20 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@8.4.20...8.4.31)

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

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

package.json

@@ -39,7 +39,7 @@
 		"eslint-plugin-vue": "^6.2.2",
 		"file-saver": "^2.0.5",
 		"floating-vue": "^2.0.0-beta.20",
-		"postcss": "^8.1.10",
+		"postcss": "^8.4.31",
 		"postcss-import": "^13.0.0",
 		"postcss-loader": "^4.1.0",
 		"postcss-nesting": "^7.0.1",