Upgrade lettre and address API changes

SmtpTransport::simple_builder() automatically validates the TLS
certificate against the provided domain name.

Author: jtgeibel

Cargo.lock

@@ -55,10 +55,12 @@ comrak = { version = "0.2.3", default-features = false }
 ammonia = "1.0.0"
 docopt = "0.8.1"
 itertools = "0.7.0"
-lettre = "0.6"
 scheduled-thread-pool = "0.2.0"
 derive_deref = "1.0.0"
 
+lettre = "0.7"
+lettre_email = "0.7"
+
 conduit = "0.8"
 conduit-conditional-get = "0.8"
 conduit-cookie = "0.8"

Cargo.toml

@@ -2,12 +2,13 @@ use dotenv::dotenv;
 use std::env;
 use std::path::Path;
 use util::{bad_request, CargoResult};
-use lettre::email::{Email, EmailBuilder};
-use lettre::transport::file::FileEmailTransport;
-use lettre::transport::EmailTransport;
-use lettre::transport::smtp::{SecurityLevel, SmtpTransportBuilder};
-use lettre::transport::smtp::SUBMISSION_PORT;
-use lettre::transport::smtp::authentication::Mechanism;
+
+use lettre::file::FileEmailTransport;
+use lettre::EmailTransport;
+use lettre::smtp::SmtpTransport;
+use lettre::smtp::authentication::{Credentials, Mechanism};
+
+use lettre_email::{Email, EmailBuilder};
 
 #[derive(Debug)]
 pub struct MailgunConfigVars {
@@ -60,20 +61,21 @@ pub fn send_email(recipient: &str, subject: &str, body: &str) -> CargoResult<()>
 
     match mailgun_config {
         Some(mailgun_config) => {
-            let mut transport =
-                SmtpTransportBuilder::new((mailgun_config.smtp_server.as_str(), SUBMISSION_PORT))?
-                    .credentials(&mailgun_config.smtp_login, &mailgun_config.smtp_password)
-                    .security_level(SecurityLevel::AlwaysEncrypt)
-                    .smtp_utf8(true)
-                    .authentication_mechanism(Mechanism::Plain)
-                    .build();
+            let mut transport = SmtpTransport::simple_builder(mailgun_config.smtp_server)?
+                .credentials(Credentials::new(
+                    mailgun_config.smtp_login,
+                    mailgun_config.smtp_password,
+                ))
+                .smtp_utf8(true)
+                .authentication_mechanism(Mechanism::Plain)
+                .build();
 
-            let result = transport.send(email.clone());
+            let result = transport.send(&email);
             result.map_err(|_| bad_request("Error in sending email"))?;
         }
         None => {
             let mut sender = FileEmailTransport::new(Path::new("/tmp"));
-            let result = sender.send(email.clone());
+            let result = sender.send(&email);
             result.map_err(|_| bad_request("Email file could not be generated"))?;
         }
     }

src/email.rs

@@ -22,6 +22,7 @@ extern crate git2;
 extern crate hex;
 extern crate htmlescape;
 extern crate lettre;
+extern crate lettre_email;
 extern crate license_exprs;
 #[macro_use]
 extern crate log;