Bump @webref/css from 6.20.9 to 6.20.10 (#2365)

Author: dependabot[bot]

package-lock.json

@@ -97,7 +97,7 @@
     "@types/superagent": "^8.1.9",
     "@types/webidl2": "^24.4.3",
     "@types/yargs": "^17.0.33",
-    "@webref/css": "6.20.9",
+    "@webref/css": "6.20.10",
     "@webref/elements": "^2.4.0",
     "@webref/idl": "3.62.1",
     "c8": "10.1.3",