build(deps-dev): bump autoprefixer from 10.4.17 to 10.4.21

Bumps [autoprefixer](https://github.com/postcss/autoprefixer) from 10.4.17 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@10.4.17...10.4.21)

---
updated-dependencies:
- dependency-name: autoprefixer
  dependency-version: 10.4.21
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

package-lock.json

@@ -87,7 +87,7 @@
     "@web/test-runner": "0.19.0",
     "@web/test-runner-commands": "0.9.0",
     "@web/test-runner-playwright": "0.11.0",
-    "autoprefixer": "10.4.17",
+    "autoprefixer": "10.4.21",
     "babel-loader": "9.1.3",
     "chromatic": "11.27.0",
     "element-internals-polyfill": "1.3.10",