Merge branch '2' into 3.0

Author: github-actions[bot]

src/File.php

@@ -1484,6 +1484,11 @@ public static function getAllowedExtensions()
                 continue;
             }
 
+            // don't add the same extension multiple times
+            if (in_array($key, $allowedExtensions)) {
+                continue;
+            }
+
             $allowedExtensions[] = $key;
         }
         return $allowedExtensions;