Swift 5 support.

[HungNMMobile]

When i try to update my project to swift 5.0. I cant build with carthage with error:
SWIFT_VERSION '3.0' is unsupported, supported versions are: 4.0, 4.2, 5.0. (in target 'JSONCodable iOS' from project 'JSONCodable')

Please update the library for support swift 5. Thank you very much!