Incrementing version to 1.13.3

Made a mistake in previous release by not incrementing the version number here. Will release a new version rather than simply updating the 1.13.2 version.

Plugin.php

@@ -157,7 +157,7 @@ public function getPluginAuthor()
 
     public function getPluginVersion()
     {
-        return '1.13.1';
+        return '1.13.3';
     }
 
     public function getPluginHomepage()