Update `Result` dependency to latest (4.0.0)

[RickDT]

Hyperspace's depending on Result 3.x conflicts with projects that are already using Result 4.x.

[tylermilner]

Hi @RickDT, thanks for bringing this up. We're using Result 4.0 on the feature/swift4.2 branch if you want to point your project over there for the time being. Once iOS 12 and the final version of Xcode 10 drop next week, we'll be releasing a new version of Hyperspace based on this branch.

[RickDT]

Thanks 👍

[tylermilner]

@RickDT just FYI, we released version 2.1.0 today. The feature/swift4.2 branch has been deleted in case you see builds failing.

[RickDT]

Woot! Thank you.