Fix __traitConstruct() should return

Signed-off-by: Nguyen Van Nguyen <nguyennv1981@gmail.com>

Author: nguyennv

src/Mail/Struct/SetCalendarItemInfoTrait.php

@@ -62,6 +62,7 @@ public function __construct(
     {
         $this->partStat = $partStat;
         $this->msg = $msg;
+        return $this;
     }
 
     /**