Bump postcss-loader from 4.0.3 to 4.3.0 (#3687)

Bumps [postcss-loader](https://github.com/webpack-contrib/postcss-loader) from 4.0.3 to 4.3.0.
- [Release notes](https://github.com/webpack-contrib/postcss-loader/releases)
- [Changelog](https://github.com/webpack-contrib/postcss-loader/blob/v4.3.0/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/postcss-loader/compare/v4.0.3...v4.3.0)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -358,7 +358,7 @@
     "nodemon": "^2.0.12",
     "playwright": "^1.14.0",
     "postcss": "^8.3.6",
-    "postcss-loader": "4.0.3",
+    "postcss-loader": "4.3.0",
     "postinstall-postinstall": "^2.1.0",
     "progress-bar-webpack-plugin": "^2.1.0",
     "randomcolor": "^0.6.2",