title: I want to get System Messages Channel in discord.js v12
body: <p>I want to get <code>SystemChannel</code>. I am using discord.js v12, this is what I have so far:</p>
  
  <pre class="lang-js prettyprint-override"><code>bot.on('guildMemberAdd', member =&gt; {
  
  // I want to get this channel, not by name
  [System Messages Channel][1]
  
  const channel = (getDefaultChannel) 
  if(!channel) return;
  channel.send(`hello ${member}!`);
  });
  </code></pre>