Remove outdated doctrine/cache package and change configuration

CloudObjects/SDK/Exceptions/InvalidSDKConfigurationException.php

@@ -0,0 +1,14 @@
+<?php
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+ 
+namespace CloudObjects\SDK\Exceptions;
+
+/**
+ * An Exception that is thrown when the SDK's configuration isn't valid.
+ */
+class InvalidSDKConfigurationException extends \Exception {
+
+}