Replace update_attributes by update in data migrations

Method update_attributes is deprecated and will be removed from Rails
6.1

src/api/db/data/20170831143534_convert_notifications_event_payload_to_json.rb

@@ -3,7 +3,7 @@ def self.up
     Notification20170831143534.transaction do
       Notification20170831143534.all.find_each do |notification|
         json = yaml_to_json(notification.event_payload)
-        notification.update_attributes!(event_payload: json)
+        notification.update!(event_payload: json)
       end
     end
   end

src/api/db/data/20180214132015_project_log_entry_user_name.rb

@@ -4,7 +4,7 @@ def up
       batch.each do |log_entry|
         user = User.find_by(id: log_entry.user_name).try(:login)
         user ||= User::NOBODY_LOGIN
-        log_entry.update_attributes(user_name: user)
+        log_entry.update(user_name: user)
       end
     end
   end
@@ -14,7 +14,7 @@ def down
       batch.each do |log_entry|
         user = User.find_by(login: log_entry.user_name).try(:id)
         user ||= User.find_nobody!.try(:id)
-        log_entry.update_attributes(user_name: user)
+        log_entry.update(user_name: user)
       end
     end
   end