build(deps-dev): downgrade postcss-advanced-variables to 3.0.1 because it didn't work

Author: iOvergaard

package-lock.json

@@ -102,7 +102,7 @@
     "npm-check-updates": "16.10.16",
     "plop": "3.1.2",
     "postcss": "8.4.36",
-    "postcss-advanced-variables": "4.0.0",
+    "postcss-advanced-variables": "3.0.1",
     "postcss-cli": "11.0.0",
     "postcss-color-function": "4.1.0",
     "postcss-custom-properties": "13.3.4",