Add Upload count to usage data

lib/gitlab/usage_data.rb

@@ -41,6 +41,7 @@ module Gitlab
             services: Service.where(active: true).count,
             snippets: Snippet.count,
             todos: Todo.count,
+            uploads: Upload.count,
             web_hooks: WebHook.count
           }
         }

spec/lib/gitlab/usage_data_spec.rb

@@ -49,6 +49,7 @@ describe Gitlab::UsageData do
         services
         snippets
         todos
+        uploads
         web_hooks
       ))
     end