Bump autoprefixer from 10.4.19 to 10.4.20 (#4506)

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

@@ -45,7 +45,7 @@
     "vt-pbf": "^3.1.3"
   },
   "devDependencies": {
-    "autoprefixer": "^10.4.19",
+    "autoprefixer": "^10.4.20",
     "@mapbox/mapbox-gl-rtl-text": "^0.3.0",
     "@mapbox/mvt-fixtures": "^3.10.0",
     "@rollup/plugin-commonjs": "^26.0.1",