Update unit tests to match current library.

Author: ruscoe

tests/MailchimpEcommerceTest.php

@@ -586,6 +586,7 @@ public function testAddProduct() {
     $store_id = 'MC001';
     $id = 'sku0001';
     $title = 'Test Product 001';
+    $url = 'http://example.org/';
     $variant_1 = (object) [
       'id' => 'PROD001A',
       'title' => "Freddie's Jokes Volume 1",
@@ -596,7 +597,7 @@ public function testAddProduct() {
 
     $mc = new MailchimpEcommerce();
 
-    $mc->addProduct($store_id, $id, $title, $variants);
+    $mc->addProduct($store_id, $id, $title, $url, $variants);
     $this->assertEquals('POST', $mc->getClient()->method);
 
     $this->assertEquals($mc->getEndpoint() . '/ecommerce/stores/' . $store_id . '/products', $mc->getClient()->uri);

tests/src/MailchimpEcommerce.php

@@ -59,7 +59,7 @@ public function getStore($store_id, $parameters = []) {
   /**
    * @inheritdoc
    */
-  public function addStore($id, $store, $batch = FALSE) {
+  public function addStore($id, $store, $parameters = [], $batch = FALSE) {
     parent::addStore($id, $store, $batch);
 
     $parameters = [