don't upgrade mailer

Author: simonLeary42

Diff for: composer.json

@@ -2,7 +2,7 @@
     "require": {
         "psr/log": "1.1.4",
         "phpseclib/phpseclib": "3.0.43",
-        "phpmailer/phpmailer": "6.9.3",
+        "phpmailer/phpmailer": "6.6.4",
         "hakasapl/phpopenldaper": "1.0.5"
     }
 }