Log Message:
Update to 5.0. From the changelog:

- new release numbering scheme; previous version numbers were just getting
  too high.
- catch and ignore/exit cleanly after reset connection in IMAP IDLE mode.
  Thanks:  Stephan Schulz.
- allow specifying an expected SSL certificate hostname, for when the
  server's certificate does not match the domain name used to connect to
  it.  Thanks:  "Andre".
- fix error message not actually giving the header field name incorrectly
  specified as containing the envelope recipient address.  Thanks:  Hardy
  Braunsdorf.
- add new password_command configuration parameter for retrievers, allowing
  getmail to retrieve the account password from any arbitrary external
  command.  Suggestion:  "ng0".