Update dependency autoprefixer to v10.4.21

Author: renovate[bot]

package.json

@@ -24,7 +24,7 @@
     "@unocss/preset-wind": "0.65.4",
     "astro-robots-txt": "0.5.0",
     "astro-seo": "0.8.4",
-    "autoprefixer": "10.4.20",
+    "autoprefixer": "10.4.21",
     "cspell": "6.31.3",
     "cssnano": "6.1.2",
     "cssnano-preset-advanced": "6.1.2",