Bump postcss and autoprefixer

Bumps [postcss](https://github.com/postcss/postcss) to 8.4.31 and updates ancestor dependency [autoprefixer](https://github.com/postcss/autoprefixer). These dependencies need to be updated together.


Updates `postcss` from 7.0.39 to 8.4.31
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@7.0.39...8.4.31)

Updates `autoprefixer` from 9.7.2 to 10.4.16
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/main/CHANGELOG.md)
- [Commits](postcss/autoprefixer@9.7.2...10.4.16)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
- dependency-name: autoprefixer
  dependency-type: direct:development
...

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

package.json

@@ -21,7 +21,7 @@
     "node-sass": "^8.0.0"
   },
   "devDependencies": {
-    "autoprefixer": "^9.7.2",
+    "autoprefixer": "^10.4.16",
     "nodemon": "^2.0.1",
     "npm-run-all": "^4.1.5",
     "postcss-cli": "^10.1.0"