feat: change scheduleReply's visibility to use it in child classes (#…

…1480)

Signed-off-by: Daniel Kesselberg <[email protected]>

lib/CalDAV/Schedule/Plugin.php

@@ -968,7 +968,7 @@ protected function getFreeBusyForEmail($email, \DateTimeInterface $start, \DateT
      *
      * @return bool
      */
-    private function scheduleReply(RequestInterface $request)
+    protected function scheduleReply(RequestInterface $request)
     {
         $scheduleReply = $request->getHeader('Schedule-Reply');