Fixing Invoice Phone Attribute

- Also updated the Update Invoice Sample

sample/invoice/UpdateInvoice.php

@@ -8,14 +8,21 @@
 $invoice = require 'CreateInvoice.php';
 use PayPal\Api\Invoice;
 
-// ### Update Invoice
-// Lets update some information
-$invoice->setInvoiceDate("2014-11-16 PST");
-
-
 // For Sample Purposes Only.
 $request = clone $invoice;
 
+// ### Update Invoice
+// Lets update some information
+$invoice->setInvoiceDate("2014-12-16 PST");
+
+// ### NOTE: These are the work-around added to the
+// sample, to get past the bug in PayPal APIs.
+// There is already an internal ticket #PPTIPS-1932 created for it.
+$invoice->setDiscount(null);
+$billingInfo = $invoice->getBillingInfo()[0];
+$billingInfo->setAddress(null);
+$invoice->getPaymentTerm()->setDueDate(null);
+
 try {
     // ### Update Invoice
     // Update an invoice by calling the invoice->update() method