Look for default SES env var from template-infra (#128)

Related to navapbc/template-infra#942

Author: doshitan

template/{{app_name}}/app/mailers/application_mailer.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
 class ApplicationMailer < ActionMailer::Base
-  default from: ENV["SES_EMAIL"]
+  default from: ENV["AWS_SES_FROM_EMAIL"] || ENV["SES_EMAIL"]
   layout "mailer"
 end