v3.3

Changelog:

• Possibility to delete older backup files #61
• Provide support for HAProxy proxy protocol #63
• allow client certificate authentication in checksync binds #64
• Option to convert slapd.conf to cn=config at each startup #66

See also https://github.com/ltb-project/slapd-cli/milestone/12

Thanks to contributors:

• @damiencassu
• @coudot
• @davidcoutadeur