maddy 0.9.1

⚠️ rspamd integration is broken in 0.9.1, use 0.9.2.

Important changes

• libdns: Deprecate libdns providers not updated for libdns 1.x

0.9.1 is (probably) the last release to support the following libdns
providers for ACME DNS challenge:

• vultr
• namedotcom
• leaseweb

0.9.1 is also the last release to supprt libdns.gandi with API
tokens, 0.10.0 will require using new Bearer-type tokens
for authentication.

See #807 for details.

Fixes

• openmetrics: Fix initialization code (thanks @cxvqo!)
• auth/ldap, check/rspamd: Fix tls_client directive definition.
• endpoint/imap: Unbreak proxy_protocol