code: function createConversationUpdate(args, membersAdded, membersRemoved) {
      let conversationUpdateActivity = createActivity({
          type: activitytypes.conversationupdate,
          recipient: args[args.botId],
          conversationId: args.conversation.id
      });
      conversationUpdateActivity.membersAdded = membersAdded || [];
      conversationUpdateActivity.membersRemoved = membersRemoved || [];
      conversationUpdateActivity.timestamp = getIncrementedDate(100);
      return conversationUpdateActivity;
  }
docs: create ConversationUpdate Activity
  @param {*} args
  @param {ChannelAccount} from
  @param {ChannelAccount[]} membersAdded
  @param {ChannelAccount[]} membersRemoved