Fixing Invoice Phone Attribute

- Also updated the Update Invoice Sample

lib/PayPal/Api/InvoiceAddress.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace PayPal\Api;
+
+use PayPal\Common\PPModel;
+
+/**
+ * Class InvoiceAddress
+ *
+ * Base Address object used as billing address in a payment or extended for Shipping Address.
+ *
+ * @package PayPal\Api
+ *
+ * @property \PayPal\Api\Phone phone
+ */
+class InvoiceAddress extends BaseAddress 
+{
+    /**
+     * Phone number in E.123 format.
+     *
+     * @param \PayPal\Api\Phone $phone
+     * 
+     * @return $this
+     */
+    public function setPhone($phone)
+    {
+        $this->phone = $phone;
+        return $this;
+    }
+
+    /**
+     * Phone number in E.123 format.
+     *
+     * @return \PayPal\Api\Phone
+     */
+    public function getPhone()
+    {
+        return $this->phone;
+    }
+
+}