lettre/lettre v0.11.12

v0.11.12 - many docs improvements

on GitHub

Misc

• Warn against manually configuring port and tls on SMTP transport builder (#1014)
• Document variants of Tls enum (#1015)
• Fix rustdoc warnings (#1016)
• Add ContentType::TEXT_PLAIN to Message builder examples (#1017)
• Document SmtpTransport and AsyncSmtpTransport (#1018)
• Fix typo in transport builder credentials method (#1019)
• Document required system dependencies for OpenSSL (#1030)
• Improve docs for the transport::smtp module (#1031)
• Improve docs for smtp transport builder from_url (#1032)
• Replace assert! with ? on send examples (#1033)
• Warn on more pedantic clippy lints and fix them (#1035, #1036)