Bump autoprefixer from 10.4.20 to 10.4.21

Bumps [autoprefixer](https://github.com/postcss/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:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

package-lock.json

@@ -13,7 +13,7 @@
   "license": "ISC",
   "dependencies": {
     "add": "^2.0.6",
-    "autoprefixer": "^10.4.20",
+    "autoprefixer": "^10.4.21",
     "next": "^15.2.4",
     "next-sitemap": "^4.2.3",
     "nextra": "^3.2.4",