Bump autoprefixer from 10.4.20 to 10.4.21 in the dev-css-sass group

Bumps the dev-css-sass group with 1 update: [autoprefixer](https://github.com/postcss/autoprefixer).


Updates `autoprefixer` from 10.4.20 to 10.4.21
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/main/CHANGELOG.md)
- [Commits](postcss/autoprefixer@10.4.20...10.4.21)

---
updated-dependencies:
- dependency-name: autoprefixer
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dev-css-sass
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -33,7 +33,7 @@
 		"@wordpress/e2e-test-utils-playwright": "1.19.1",
 		"@wordpress/prettier-config": "4.19.1",
 		"@wordpress/scripts": "30.12.1",
-		"autoprefixer": "10.4.20",
+		"autoprefixer": "10.4.21",
 		"chalk": "5.4.1",
 		"check-node-version": "4.2.1",
 		"copy-webpack-plugin": "13.0.0",