Revert "refactor: remove is-url-superb dependency and update URL filtering logic"

Author: XhmikosR

package-lock.json

@@ -26,6 +26,7 @@
     "postcss": "^8.4.47"
   },
   "dependencies": {
+    "is-url-superb": "^4.0.0",
     "postcss-values-parser": "^6.0.2"
   },
   "devDependencies": {

package.json

@@ -79,12 +79,8 @@ function getValueOrUrl(node: ChildNode) {
   // ['file']
   const ret = isUrlNode(node) ? getValue(node.nodes[0]) : getValue(node);
 
-  // Filter out absolute URLs (http://, https://, etc.), protocol-relative URLs (//), and data URIs
-  if (/^([a-z]+:)?\/\//i.test(ret) || ret.startsWith('data:')) {
-    return false;
-  }
-
-  return ret;
+  // is-url sometimes gets data: URLs wrong
+  return !isUrl(ret) && !ret.startsWith('data:') && ret;
 }
 
 function getValue(node: ChildNode) {