Add back Account entity in Analytics class (#223)

* add back Account entity in Analytics class

Author: Pimentoso

lib/twitter-ads/resources/analytics.rb

@@ -30,6 +30,7 @@ class Analytics
     property :metric_groups, read_only: true
 
     ANALYTICS_MAP = {
+      'TwitterAds::Account' => Entity::ACCOUNT,
       'TwitterAds::Campaign' => Entity::CAMPAIGN,
       'TwitterAds::LineItem' => Entity::LINE_ITEM,
       'TwitterAds::OrganicTweet' => Entity::ORGANIC_TWEET,