fix(autoconfig): Added configuration information for ATT email accounts

Author: andris9

lib/autodetect-imap-settings.js

@@ -459,6 +459,24 @@ async function resolveUsingMX(email, domain) {
             };
         }
 
+        // ATT
+        if (/mx-vip\d*\.prodigy\.net$/i.test(exchange)) {
+            // ATT
+            return {
+                imap: {
+                    host: 'imap.mail.att.net',
+                    port: 993,
+                    secure: true
+                },
+                smtp: {
+                    host: 'smtp.mail.att.net',
+                    port: 465,
+                    secure: true
+                },
+                _source: 'mx'
+            };
+        }
+
         // Naver (kr)
         if (/^mx\d*\.naver\.com$/i.test(exchange)) {
             // Naver.com