Adding in missing PUT and DELETE for productListings

[bparise]

This change adds in PUT (via create) and DELETE for productListings endpoint

[coveralls]

Coverage decreased (-0.8%) to 99.199% when pulling abc5dc0 on bparise:patch-1 into 48c3f94 on MONEI:master.

[bparise]

Dope. Forgot test cases to cover this pull request... will do shortly

[lpinca]

Keep this as we are adding a custom version below.

[lpinca]

The example does not use an empty body. Can we do something like this?

/**
 * Creates a product listing.
 *
 * @param {Number} productId The ID of the product to publish
 * @param {Object} [params] Body parameters
 * @return {Promise} Promise that resolves with the result
 * @public
 */
ProductListing.prototype.create = function create(productId, params) {
  params || (params = { product_id: productId });
  const url = this.buildUrl(productId);
  return this.shopify.request(url, 'PUT', this.key, params);
};

[lpinca]

I think we can remove this as the default implementation

Shopify-api-node/mixins/base.js

Lines 45 to 48 in 53b6ac8

	delete(id) {
	const url = this.buildUrl(id);
	return this.shopify.request(url, 'DELETE');
	},

should work.

[lpinca]

We also need to update the documentation.

[coveralls]

Coverage remained the same at 100.0% when pulling 4668493 on bparise:patch-1 into 48c3f94 on MONEI:master.

[lpinca]

Thank you.