Fix encoding version in typed data Domain (#230)

* Change `StarknetTypedData` version type to `String`

* Remove dummy changes

* Add `Domain` encoding

* Apply code review suggestion

* Little refactor

* Little refactor

* Remove unused code

* Fix version encoding

* Fix tests

Author: franciszekjob

Sources/Starknet/Data/TypedData/StarknetTypedData.swift

@@ -399,6 +399,13 @@ public extension StarknetTypedData {
         public let chainId: Element
         public let revision: Revision
 
+        fileprivate enum CodingKeys: CodingKey {
+            case name
+            case version
+            case chainId
+            case revision
+        }
+
         public var separatorName: String {
             switch revision {
             case .v0: "StarkNetDomain"
@@ -413,6 +420,14 @@ public extension StarknetTypedData {
             self.chainId = try container.decode(Element.self, forKey: .chainId)
             self.revision = try container.decodeIfPresent(Revision.self, forKey: .revision) ?? .v0
         }
+
+        public func encode(to encoder: Encoder) throws {
+            var container = encoder.container(keyedBy: CodingKeys.self)
+            try container.encode(name, forKey: .name)
+            try container.encode(String(describing: version), forKey: .version)
+            try container.encode(chainId, forKey: .chainId)
+            try container.encode(revision, forKey: .revision)
+        }
     }
 
     enum Revision: String, Codable, Equatable {
@@ -704,6 +719,29 @@ extension StarknetTypedData {
     }
 }
 
+extension StarknetTypedData.Element: CustomStringConvertible {
+    public var description: String {
+        switch self {
+        case let .string(s):
+            s
+        case let .decimal(n):
+            String(n)
+        case let .signedDecimal(n):
+            String(n)
+        case let .felt(f):
+            f.toHex()
+        case let .signedFelt(f):
+            f.toHex()
+        case let .bool(b):
+            String(b)
+        case .object:
+            String(describing: self)
+        case .array:
+            String(describing: self)
+        }
+    }
+}
+
 private extension String {
     func strippingPointer() -> String {
         if self.isArray() {

Tests/StarknetTests/Data/TypedDataTests.swift

@@ -47,14 +47,14 @@ final class TypedDataTests: XCTestCase {
     static let exampleDomainV0 = """
     {
         "name": "DomainV0",
-        "version": 1,
+        "version": "1",
         "chainId": 2137,
     }
     """
     static let exampleDomainV1 = """
     {
         "name": "DomainV1",
-        "version": 2,
+        "version": "2",
         "chainId": "2137",
         "revision": 1
     }