Bump postcss from 8.4.5 to 8.4.31

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.5 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@8.4.5...8.4.31)

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

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

package.json

@@ -16,7 +16,7 @@
     "@vue/compiler-sfc": "^3.2.29",
     "autoprefixer": "^10.4.2",
     "laravel-mix": "^6.0.43",
-    "postcss": "^8.4.5",
+    "postcss": "^8.4.31",
     "tailwindcss": "^3.0.16",
     "vue": "^3.2.29",
     "vue-loader": "^16.8.3"