title: Get error when upgrading to laravel 7.0 From laravel 6.x
body: <p>I am trying to upgrade my application to laravel 7. But I got error when i entered <code>composer update</code>. And changed composer.json file as well as laravel upgrade document.</p>
  
  <p>And error is :</p>
  
  <blockquote>
    <p>The "<a href="http://repo.packagist.org/p/provider-2019-10%24543d5b0a9102507acbcfcd5499f758ebe96c4f5516cb7ccf042c12126ac86899.json" rel="nofollow noreferrer">http://repo.packagist.org/p/provider-2019-10%24543d5b0a9102507acbcfcd5499f758ebe96c4f5516cb7ccf042c12126ac86899.json</a>" file could not be downloaded (HTTP/1.1 503 Service Unavailable)<a href="http://repo.packagist.org" rel="nofollow noreferrer">http://repo.packagist.org</a> could not be fully loaded, package information was loaded from the local cache and may be out of date</p>
  </blockquote>
  
  <p>Why error occurred? </p>