remove type casting to allow addDynamicTemplateData to accept arrays. (#7)

Author: timstl

src/SendGridMessage.php

@@ -122,7 +122,7 @@ public function build(): Mail
         }
 
         foreach ($this->payload as $key => $value) {
-            $email->addDynamicTemplateData((string) $key, (string) $value);
+            $email->addDynamicTemplateData((string) $key, $value);
         }
 
         return $email;