Remove unnecessary Sendable requirement on JSONEncoder

Author: adam-fowler

Sources/Hummingbird/Codable/JSON/JSONCoding.swift

@@ -48,14 +48,3 @@ extension JSONDecoder: RequestDecoder {
         return try self.decode(T.self, from: buffer)
     }
 }
-
-/// `RequestDecoder` and `ResponseEncoder` both require conformance to `Sendable`. Given
-/// `JSONEncoder`` and `JSONDecoder`` conform to Sendable in macOS 13+ I think I can just
-/// back date the conformance to all versions of Swift, macOS we support
-#if hasFeature(RetroactiveAttribute)
-extension JSONEncoder: @retroactive @unchecked Sendable {}
-extension JSONDecoder: @retroactive @unchecked Sendable {}
-#else
-extension JSONEncoder: @unchecked Sendable {}
-extension JSONDecoder: @unchecked Sendable {}
-#endif