6.0.0

• geoipupdate now supports configuration via environment variables. Any
  configuration set this way will override any value from the config file,
  but still be overridden by any associated command line option (if any).
  The following new environment variables are supported:

  • GEOIPUPDATE_ACCOUNT_ID
  • GEOIPUPDATE_ACCOUNT_ID_FILE
  • GEOIPUPDATE_CONF_FILE
  • GEOIPUPDATE_DB_DIR
  • GEOIPUPDATE_EDITION_IDS
  • GEOIPUPDATE_HOST
  • GEOIPUPDATE_LICENSE_KEY
  • GEOIPUPDATE_LICENSE_KEY_FILE
  • GEOIPUPDATE_LOCK_FILE
  • GEOIPUPDATE_PARALLELISM
  • GEOIPUPDATE_PRESERVE_FILE_TIMES
  • GEOIPUPDATE_PROXY
  • GEOIPUPDATE_PROXY_USER_PASSWORD
  • GEOIPUPDATE_RETRY_FOR
  • GEOIPUPDATE_VERBOSE

• Changed the signature of NewConfig in pkg/geoipupdate to no longer accept
  a positional config file path argument, which can now be passed in using the
  option from WithConfigFile along with the other optional parameters.

• geoipupdate and NewConfig no longer require a config file to exist.

• The --stack-trace flag has been removed. This flag has been broken since
  4.11.0.