TT1: Update postcss

Author: desrosj

src/wp-content/themes/twentytwentyone/package-lock.json

@@ -25,7 +25,7 @@
 		"eslint": "^8.57.1",
 		"minimist": "^1.2.8",
 		"npm-run-all": "^4.1.5",
-		"postcss": "^8.4.49",
+		"postcss": "^8.5.6",
 		"postcss-calc": "^10.1.1",
 		"postcss-cli": "^11.0.1",
 		"postcss-css-variables": "^0.19.0",