Build(deps-dev): Bump autoprefixer from 10.4.19 to 10.4.20 (twbs#40697)

Bumps [autoprefixer](https://github.com/postcss/autoprefixer) from 10.4.19 to 10.4.20.
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/main/CHANGELOG.md)
- [Commits](postcss/autoprefixer@10.4.19...10.4.20)

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

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

Author: dependabot[bot]

package-lock.json

@@ -113,7 +113,7 @@
     "@rollup/plugin-node-resolve": "^15.2.3",
     "@rollup/plugin-replace": "^5.0.7",
     "@stackblitz/sdk": "^1.11.0",
-    "autoprefixer": "^10.4.19",
+    "autoprefixer": "^10.4.20",
     "bundlewatch": "^0.4.0",
     "clean-css-cli": "^5.6.3",
     "clipboard": "^2.0.11",