Update project to Swift 5 and Update Dependencies

[fbeeper]

Hello trivago!

We updated the framework and test targets (iOS and macOS) to Swift 5. We also updated all dependencies:

• Public:
  • antitypical/Result to 4.1.0 (Swift 4.2 / Compatible with Swift 5's Result)
• Private:
  • jspahrsummers/xcconfigs to 1.0 (for Xcode 10.2)
  • AliSoftware/OHHTTPStubs to 7.0 (Swift 4.2)
  • Quick/Quick to 2.1.0 (Swift 4.2)
  • Quick/Nimble to `8.0.1 (Swift 4.2)

Updates to the project were minor. All tests are passing.

Looking forward for your feedback. We'll be happy to address any changes you think would be necessary or nice to have.

Notes:

• There are some outstanding warnings showing in Xcode 10.2 for the localization that we haven't adressed.
• We updated the version number to 3.7.0 but, probably, this is something you'll like us to leave out of the PR, right?

[fbeeper]

Folks, do you need any updates? Or you are no longer mantaining this library?

[donnywdavis]

@fbeeper Hey, thank you for tackling this and sorry that this has taken so long. The project got lost in the shuffle of things and fell off of our radar. Going to see what I can do to get this merged and see if I can resurrect the project so it stays relevant. 🙂