4.0.0

• IMPORTANT: Python 2.7 and 3.5 support has been dropped. Python 3.6 or greater
  is required.
• Asyncio support has been added for web service requests. To make async
  requests, use geoip.webservice.AsyncClient.
• geoip.webservice.Client now provides a close() method and associated
  context managers to be used in with statements.
• Type hints have been added.
• The attributes postal_code and postal_confidence have been removed
  from geoip2.record.Location. These would previously always be None.
• user_id is no longer supported as a named argument for the constructor
  on geoip2.webservice.Client. Use account_id or a positional
  parameter instead.
• For both Client and AsyncClient requests, the default timeout is
  now 60 seconds.