chore(deps-dev): bump postcss from 8.5.14 to 8.5.15 (#427)

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.14 to 8.5.15.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.14...8.5.15)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.15
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

bun.lock

@@ -27,7 +27,7 @@
     "@types/mdx": "^2.0.13",
     "@types/react": "^19.2.15",
     "@types/react-dom": "^19.2.3",
-    "postcss": "^8.5.14",
+    "postcss": "^8.5.15",
     "serve": "^14.2.6",
     "tailwindcss": "^4.3.0",
     "typescript": "^6.0.3"