fix lint er

src/server/routes/apiv3/slack-integration.js

@@ -3,7 +3,6 @@ const loggerFactory = require('@alias/logger');
 const logger = loggerFactory('growi:routes:apiv3:notification-setting');
 const express = require('express');
 const { body } = require('express-validator');
-const { WebClient } = require('@slack/web-api');
 const crypto = require('crypto');
 const ErrorV3 = require('../../models/vo/error-apiv3');