update cron module

CronJob -> CronJob.from
CronJob(time) -> CronTime

src/apps.js

@@ -150,7 +150,7 @@ const appstore = require('./appstore.js'),
     backups = require('./backups.js'),
     BoxError = require('./boxerror.js'),
     constants = require('./constants.js'),
-    CronJob = require('cron').CronJob,
+    { CronTime } = require('cron'),
     dashboard = require('./dashboard.js'),
     database = require('./database.js'),
     debug = require('debug')('box:apps'),
@@ -340,7 +340,7 @@ function parseCrontab(crontab) {
             const command = parts[6];
 
             try {
-                new CronJob('00 ' + schedule, function() {}); // second is disallowed
+                new CronTime('00 ' + schedule); // second is disallowed
             } catch (ex) {
                 throw new BoxError(BoxError.BAD_FIELD, `Invalid cron pattern at line ${i+1}`);
             }