Fix crash "call to deleted method" when running tests on Xcode 14

Sources/XXClient/Helpers/JSONDecoder.swift

@@ -8,14 +8,14 @@ class JSONDecoder: Foundation.JSONDecoder {
 
   override func decode<T>(_ type: T.Type, from data: Data) throws -> T where T: Decodable {
     do {
-      let data = convertNumberToString(in: data, at: "Value")
+      let data = Self.convertNumberToString(in: data, at: "Value")
       return try super.decode(type, from: data)
     } catch {
       throw JSONDecodingError(error, data: data)
     }
   }
 
-  func convertNumberToString(
+  static func convertNumberToString(
     in input: Data,
     at key: String
   ) -> Data {

Sources/XXClient/Helpers/JSONEncoder.swift

@@ -9,14 +9,14 @@ class JSONEncoder: Foundation.JSONEncoder {
   override func encode<T>(_ value: T) throws -> Data where T: Encodable {
     do {
       var data = try super.encode(value)
-      data = convertStringToNumber(in: data, at: "Value")
+      data = Self.convertStringToNumber(in: data, at: "Value")
       return data
     } catch {
       throw JSONEncodingError(error, value: value)
     }
   }
 
-  func convertStringToNumber(
+  static func convertStringToNumber(
     in input: Data,
     at key: String
   ) -> Data {

Tests/XXClientTests/Helpers/JSONDecoderTests.swift

@@ -71,7 +71,7 @@ private func assertConvertingNumberToString(
 ) {
   XCTAssertNoDifference(
     String(
-      data: JSONDecoder().convertNumberToString(
+      data: JSONDecoder.convertNumberToString(
         in: input.data(using: .utf8)!,
         at: key
       ),

Tests/XXClientTests/Helpers/JSONEncoderTests.swift

@@ -71,7 +71,7 @@ private func assertConvertingStringToNumber(
 ) {
   XCTAssertNoDifference(
     String(
-      data: JSONEncoder().convertStringToNumber(
+      data: JSONEncoder.convertStringToNumber(
         in: input.data(using: .utf8)!,
         at: key
       ),