The `getSubscriptionItem` function does not check `subscriptionItemId` as a required parameter

[keyding]

The getSubscriptionItem function does not check subscriptionItemId as a required parameter.

source code:

lemonsqueezy.js/src/subscriptionItems/index.ts

Lines 18 to 33 in 9c9b03a

	/**
	* Retrieve a subscription item.
	*
	* @param subscriptionItemId The given subscription item id.
	* @param [params] (Optional) Additional parameters.
	* @param [params.include] (Optional) Related resources.
	* @returns A subscription item object.
	*/
	export function getSubscriptionItem(
	subscriptionItemId: number | string,
	params: GetSubscriptionItemParams = {}
	) {
	return $fetch<SubscriptionItem>({
	path: `/v1/subscription-items/${subscriptionItemId}${convertIncludeToQueryString(params.include)}`,
	});
	}

Fixed code:

/**
 * Retrieve a subscription item.
 *
 * @param subscriptionItemId The given subscription item id.
 * @param [params] (Optional) Additional parameters.
 * @param [params.include] (Optional) Related resources.
 * @returns A subscription item object.
 */
export function getSubscriptionItem(
  subscriptionItemId: number | string,
  params: GetSubscriptionItemParams = {}
) {
  requiredCheck({ subscriptionItemId });
  return $fetch<SubscriptionItem>({
    path: `/v1/subscription-items/${subscriptionItemId}${convertIncludeToQueryString(params.include)}`,
  });
}

[keyding]

I've fixed it. PR #73