Bump postcss from 8.4.1 to 8.4.4

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.1 to 8.4.4.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.4.1...8.4.4)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

package.json

@@ -17,7 +17,7 @@
         "font-awesome": "^4.7.0",
         "jquery": "^3",
         "laravel-mix": "^6.0",
-        "postcss": "^8.3",
+        "postcss": "^8.4",
         "uiv": "^1.4",
         "vue": "^2.6",
         "vue-i18n": "^8.26",