Restore defaultForCurrency variable in the Card (#238)

* Rollback defaultForCurrency variable in the Card

* Add subscription_details to Invoice

* Make SubscriptionDetails codable

* Add subscription_details to PaymentIntent

* Revert "Add subscription_details to PaymentIntent"

This reverts commit 745c48c.

* Add defaultForCurrency to the initializer

* Add subscriptionDetails to the initializer

* Add a public initializer for SubscriptionDetails

* Add a default nil param for SubscriptionDetails init

Sources/StripeKit/Billing/Invoices/Invoice.swift

@@ -40,6 +40,8 @@ public struct Invoice: Codable {
     public var status: InvoiceStatus?
     /// The subscription that this invoice was prepared for, if any.
     @Expandable<Subscription> public var subscription: String?
+	/// Details about the subscription that created this invoice.
+	public var subscriptionDetails: SubscriptionDetails?
     /// Total after discount.
     public var total: Int?
     /// String representing the object’s type. Objects of the same type share the same value.
@@ -178,6 +180,7 @@ public struct Invoice: Codable {
                 periodStart: Date? = nil,
                 status: InvoiceStatus? = nil,
                 subscription: String? = nil,
+				subscriptionDetails: SubscriptionDetails? = nil,
                 total: Int? = nil,
                 object: String,
                 accountCountry: String? = nil,
@@ -254,6 +257,7 @@ public struct Invoice: Codable {
         self.periodStart = periodStart
         self.status = status
         self._subscription = Expandable(id: subscription)
+		self.subscriptionDetails = subscriptionDetails
         self.total = total
         self.object = object
         self.accountCountry = accountCountry
@@ -318,6 +322,15 @@ public struct Invoice: Codable {
     }
 }
 
+public struct SubscriptionDetails: Codable {
+	/// Set of key-value pairs that you can attach to an object. This can be useful for storing additional information about the object in a structured format.
+	public var metadata: [String: String]?
+
+	public init(metadata: [String: String]? = nil) {
+		self.metadata = metadata
+	}
+}
+
 public enum InvoiceCollectionMethod: String, Codable {
     case chargeAutomatically = "charge_automatically"
     case sendInvoice = "send_invoice"

Sources/StripeKit/Payment Methods/Cards/Card.swift

@@ -32,6 +32,8 @@ public struct Card: Codable {
     @Expandable<Customer> public var customer: String?
     /// If a CVC was provided, results of the check: `pass`, `fail`, `unavailable`, or `unchecked`.
     public var cvcCheck: CardValidationCheck?
+	/// Whether this card is the default external account for its currency.
+	public var defaultForCurrency: Bool?
     /// Two-digit number representing the card’s expiration month.
     public var expMonth: Int?
     /// Four-digit number representing the card’s expiration year.
@@ -87,6 +89,7 @@ public struct Card: Codable {
                 addressLine1Check: CardValidationCheck? = nil,
                 availablePayoutMethods: [String]? = nil,
                 currency: Currency? = nil,
+				defaultForCurrency: Bool? = nil,
                 dynamicLast4: String? = nil,
                 tokenizationMethod: CardTokenizedMethod? = nil,
                 wallet: CardWallet? = nil) {
@@ -114,6 +117,7 @@ public struct Card: Codable {
         self.addressLine1Check = addressLine1Check
         self.availablePayoutMethods = availablePayoutMethods
         self.currency = currency
+		self.defaultForCurrency = defaultForCurrency
         self.dynamicLast4 = dynamicLast4
         self.tokenizationMethod = tokenizationMethod
         self.wallet = wallet