update kirby to v5 and add refresh cache panel view button

public/kirby/src/Email/Email.php

@@ -53,7 +53,9 @@ class Email
 	{
 		foreach (['body', 'from', 'to', 'subject'] as $required) {
 			if (isset($props[$required]) === false) {
-				throw new InvalidArgumentException('The property "' . $required . '" is required');
+				throw new InvalidArgumentException(
+					message: 'The property "' . $required . '" is required'
+				);
 			}
 		}
 

public/kirby/src/Email/PHPMailer.php

@@ -99,7 +99,9 @@ class PHPMailer extends Email
 			$mailer = $beforeSend->call($this, $mailer) ?? $mailer;
 
 			if ($mailer instanceof Mailer === false) {
-				throw new InvalidArgumentException('"beforeSend" option return should be instance of PHPMailer\PHPMailer\PHPMailer class');
+				throw new InvalidArgumentException(
+					message: '"beforeSend" option return should be instance of PHPMailer\PHPMailer\PHPMailer class'
+				);
 			}
 		}