feat: support for additional SMTP client options

config/initializers/smtp.rb

@@ -2,10 +2,17 @@
 
 require "postal/config"
 
+config = Postal::Config.smtp
+
 ActionMailer::Base.delivery_method = :smtp
 ActionMailer::Base.smtp_settings = {
-  address: Postal::Config.smtp.host,
-  user_name: Postal::Config.smtp.username,
-  password: Postal::Config.smtp.password,
-  port: Postal::Config.smtp.port
+  address: config.host,
+  user_name: config.username,
+  password: config.password,
+  port: config.port,
+  authentication: config.authentication_type&.to_sym,
+  enable_starttls: config.enable_starttls?,
+  enable_starttls_auto: config.enable_starttls_auto?,
+  openssl_verify_mode: config.openssl_verify_mode,
+  ssl: config.ssl?
 }