Update dependency postcss to v8.5.31 (#4559)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

package-lock.json

@@ -17,7 +17,7 @@
         "ckeditor5": "49.0.0",
         "esbuild": "0.28.2",
         "github-markdown-css": "5.9.0",
-        "postcss": "8.5.30",
+        "postcss": "8.5.31",
         "purgecss": "8.0.0",
         "sass": "1.105.2",
         "svg-sprite": "2.0.4",
@@ -5013,9 +5013,9 @@
       }
     },
     "node_modules/postcss": {
-      "version": "8.5.30",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.30.tgz",
-      "integrity": "sha512-zkd+e9S1AQHhmaBKye9zlFHWjOwVgqXl1q3ECYy8561K7qxR2cREf/STLskulBFd78k6AOFeA+ff1TtEzk9bAA==",
+      "version": "8.5.31",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.31.tgz",
+      "integrity": "sha512-YUbWYCgErwnMAVkjUnYa+KlMBzGpHwiIt/DE7f0G33AuX2LH9UcTk6KgWxd3zRU+pN3u/C+Xl3EnMLM4Hea7Sg==",
       "dev": true,
       "funding": [
         {

package.json

@@ -36,7 +36,7 @@
     "ckeditor5": "49.0.0",
     "esbuild": "0.28.2",
     "github-markdown-css": "5.9.0",
-    "postcss": "8.5.30",
+    "postcss": "8.5.31",
     "purgecss": "8.0.0",
     "sass": "1.105.2",
     "svg-sprite": "2.0.4",