Fix array key naming inconsistency

Summary: Issue fixed in #628

Reviewed By: liliarizona

Differential Revision: D71211317

fbshipit-source-id: 2a2a4a973d30c4acb8b16a684e3ec6b0684b8419

Author: satwikareddy3

Diff for: src/FacebookAds/Object/ServerSide/Event.php

@@ -574,8 +574,8 @@ public function getOriginalEventData() {
    * Sets the attribution data of the event.
    * @return $this
    */
-  public function setAttributionData($attribute_data) {
-    $this->container['attribute_data'] = $attribute_data;
+  public function setAttributionData($attribution_data) {
+    $this->container['attribution_data'] = $attribution_data;
     return $this;
   }