Enforcing 40 character limit for Square reference_id

src/SquarepayExtension.php

@@ -269,7 +269,7 @@ class SquarepayExtension extends SimpleExtension
 			$paymentInfo['order_id'] = $orderId;
 		}
 		$referenceInfo = [
-			'reference_id' => $name.' <'.$email.'>',
+			'reference_id' => substr($name, 0, 40),
 			'note' => $booker.' on '.$date
 		];