title: Search product with woocommerce REST API by sku
body: <p>I have to create a service in order to publish products to a wordpress via woocommerce REST API.<br />
  We are creating products in site by using the batch update &quot;function&quot;.<br />
  All nice and fine, but I cannot search if a product already exist in order to not multiply (or get error on insert) by anything else except the id.<br />
  Is there a way to search for a product by sku?<br />
  tks</p>