meta: bump postcss from 8.4.39 to 8.4.40 (#6972)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.39 to 8.4.40.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.39...8.4.40)

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

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

Author: dependabot[bot]

apps/site/package.json

@@ -69,7 +69,7 @@
     "next": "~14.2.4",
     "next-intl": "~3.15.3",
     "next-themes": "~0.3.0",
-    "postcss": "~8.4.38",
+    "postcss": "~8.4.40",
     "postcss-calc": "~10.0.0",
     "postcss-import": "~16.1.0",
     "postcss-mixins": "~10.0.1",