fix(@angular-devkit/build-angular): upgrade postcss to 8.5.12

This addresses GHSA-qx2v-qp2m-jg93

Fixes: #33067

Author: alan-agius4

package.json

@@ -170,7 +170,7 @@
     "parse5-html-rewriting-stream": "7.0.0",
     "picomatch": "4.0.4",
     "piscina": "4.8.0",
-    "postcss": "8.5.2",
+    "postcss": "8.5.12",
     "postcss-loader": "8.1.1",
     "prettier": "^3.0.0",
     "protractor": "~7.0.0",

packages/angular_devkit/build_angular/package.json

@@ -44,7 +44,7 @@
     "ora": "5.4.1",
     "picomatch": "4.0.4",
     "piscina": "4.8.0",
-    "postcss": "8.5.2",
+    "postcss": "8.5.12",
     "postcss-loader": "8.1.1",
     "resolve-url-loader": "5.0.0",
     "rxjs": "7.8.1",