Swift 5 support 🎉

Thanks to @shark-sea and @Dschee to add Swift 5 support and update the SwiftPM.

API breaking changes

N/A

Enhancements

• Support Swift 5.0 #603 by @shark-sea
• Update SwiftPM manifest file to support Accio #608 by @Dschee

Bugfixes

N/A