Add SwiftGodot

[TheConnorJohnson]

• SwiftGodot:
• https://migueldeicaza.github.io/SwiftGodotDocs/tutorials/swiftgodot-tutorials/:
• Swift bindings for the Godot game engine to build extensions or act as an api with SwiftGodotKit.:
• Why it should be added to awesome-swift:
• At least 15 stars (GitHub project)
• Support Swift 5
• Updated contents.json instead of README
• Lib is fully open sourced, written in Swift and not a wrapper over compiled lib
• Description does not say "written in Swift" or variant 🤓

[matteocrippa]

thx @TheConnorJohnson