Resolve required-after-optional param deprecations

Just setting to `null` for now to get past the errors. This isn’t the time to refactor.

Author: AkenRoberts

src/Uploadable/UploadableListener.php

@@ -467,7 +467,7 @@ public function removeFile($filePath)
      * @throws \Gedmo\Exception\UploadableNoTmpDirException
      * @throws \Gedmo\Exception\UploadableCantWriteException
      */
-    public function moveFile(FileInfoInterface $fileInfo, $path, $filenameGeneratorClass = false, $overwrite = false, $appendNumber = false, $object)
+    public function moveFile(FileInfoInterface $fileInfo, $path, $filenameGeneratorClass = false, $overwrite = false, $appendNumber = false, $object = null)
     {
         if ($fileInfo->getError() > 0) {
             switch ($fileInfo->getError()) {

tests/Gedmo/Sluggable/Fixture/Issue939/SluggableListener.php

@@ -18,7 +18,7 @@ public function __construct()
         $this->setUrlizer([$this, 'urlizer']);
     }
 
-    public function transliterator($slug, $separator = '-', $object)
+    public function transliterator($slug, $separator = '-', $object = null)
     {
         if ($object instanceof Article) {
             // custom transliteration here
@@ -31,7 +31,7 @@ public function transliterator($slug, $separator = '-', $object)
         );
     }
 
-    public function urlizer($slug, $separator = '-', $object)
+    public function urlizer($slug, $separator = '-', $object = null)
     {
         if ($object instanceof Article) {
             // custom urlization here