Merge branch 'bugfix/use-correct-method-to-add-text-to-mail' into 'develop'

[BUGFIX] Use text method to add rendered content to mail

See merge request t3o/ter!577

extensions/ter/Classes/Api/ExtensionVersion.php

@@ -713,7 +713,7 @@ class ExtensionVersion
                         'extData' => $extensionData
                     ]
                 );
-                $mail->setBody($standalone->render());
+                $mail->text($standalone->render());
 
                 $mail->send();
             }