[PHP8対応] パスワード再設定時のエラーを修正 (#1086)

Co-authored-by: Jun Matsuda <{ID}+{username}@users.noreply.github.com>

modules/Vtiger/helpers/ShortURL.php

@@ -85,7 +85,7 @@ static function sendTrackerImage() {
 		echo base64_decode('iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAApJREFUCNdjYAAAAAIAAeIhvDMAAAAASUVORK5CYII=');
 	}
 
-	function getInstance($id) {
+	static function getInstance($id) {
 		$db = PearDatabase::getInstance();
 		$self = new self();
 		$rs = $db->pquery('SELECT * FROM vtiger_shorturls WHERE uid=?', array($id));