chore(deps-dev): bump postcss from 8.4.21 to 8.4.39

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.21 to 8.4.39.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.21...8.4.39)

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

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -90,7 +90,7 @@
     "jest-environment-jsdom": "^29.7.0",
     "lint-staged": "12.3.4",
     "nock": "13.2.4",
-    "postcss": "8.4.21",
+    "postcss": "8.4.39",
     "postcss-loader": "4.3.0",
     "prettier": "2.5.1",
     "react-dev-utils": "12.0.0",