title: Can not connect via AsyncSSH, error Host key is not trusted
body: <p>When I run this script I receive <code>SSH connection failed: Host key is not trusted</code> error, but even connect to this host to take the key, keep to receive this error.</p>
  <pre><code>import asyncio, asyncssh, sys
  
  async def run_client():
      async with asyncssh.connect('172.18.17.9', username=&quot;user&quot;, password=&quot;admin&quot;, port=9321) as conn:
          result = await conn.run('display version', check=True)
          print(result.stdout, end='')
  
  try:
      asyncio.get_event_loop().run_until_complete(run_client())
  except (OSError, asyncssh.Error) as exc:
      sys.exit('SSH connection failed: ' + str(exc))
  </code></pre>