Carthage now requires Swift 4.0 / Xcode 9.

Fixed

• jsonDecodingError is incorrectly reported when downloading binaries (#2182). Thanks @ikesyo!

Improved

• Use archive action when building device SDKs to disable LLVM Instrumentation (#2158). Thanks @ikesyo!

Thank you to @kas-kad for improvements to documentation. Thank you to @ikesyo and @mdiep for improvements to the codebase! Thanks to @BobElDevil, @ikesyo, @jdhealy, @mdiep and @NachoSoto for reviewing pull requests!