Implemented the AmiiboUsage model.

Sources/Models/AmiiboUsage.swift

@@ -0,0 +1,15 @@
+extension Amiibo {
+    public struct Usage {
+        public let explanation: String
+        public let isWritable: Bool
+    }
+}
+
+// MARK: - Decodable
+
+extension Amiibo.Usage: Decodable {
+    enum CodingKeys: String, CodingKey {
+        case explanation = "Usage"
+        case isWritable = "write"
+    }
+}