Added package initializers to the Amiibo models for testing.

Sources/AmiiboService/Public/Models/Amiibo/Amiibo+Release.swift

@@ -36,6 +36,19 @@ extension Amiibo {
         
         // MARK: Initializers
 
+        /// Initializes this model.
+        package init(
+            america: Date? = nil,
+            australia: Date? = nil,
+            europe: Date? = nil,
+            japan: Date? = nil
+        ) {
+            self.america = america
+            self.australia = australia
+            self.europe = europe
+            self.japan = japan
+        }
+
         /// Initializes this model from a given payload.
         /// - Parameter payload: A payload that contains the values for the model.
         init(_ payload: Components.Schemas.AmiiboRelease) {