Bump postcss from 8.4.17 to 8.4.20

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.17 to 8.4.20.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.17...8.4.20)

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

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

Author: dependabot[bot]

package-lock.json

@@ -59,7 +59,7 @@
     "fs-extra": "^10.1.0",
     "happy-dom": "^7.1.1",
     "lodash": "^4.17.21",
-    "postcss": "^8.4.17",
+    "postcss": "^8.4.20",
     "rimraf": "^3.0.2",
     "tailwindcss": "^3.1.8",
     "typescript": "^4.8.4",