lezhin: don't unset user-agent

lezhin/download.js

@@ -1,6 +1,6 @@
 (async function () {
-  const got = require('got')
   const fs = require('fs')
+  const got = require('got')
   const util = require('util')
 
   const SKIP = parseInt(process.env.SKIP) || 0
@@ -31,7 +31,6 @@
       headers: {
         'Accept': 'application/json',
         'Authorization': `Bearer ${TOKEN}`,
-        'user-agent': undefined
       }
     }
     let response = await got(signing_url, options)