Log Message:
Update to 4.5.1. From the changelog:

- add delete_dup_msgids option to non-multidrop POP3 retrievers.
    Thanks: Matthias Andree.
- suppress stack trace in getmail_fetch error message when
    configuration error detected. Thanks: Dave Jarvis.
- documentation updates.
- build and development environment changes. The plaintext versions
    of the documentation are now generated with links instead of lynx.
- explicitly log the reason for not retrieving a message (seen or
    oversized). Thanks: Payal Rathod.