Update Swift CI, etc. for Xcode 10.2 beta 2

[CTMacUser (Daryle Walker)]

Apple's Swift repository still lists the original Xcode 10.2 beta. I already moved on to the second beta. Is the Swift compilation setup going to move there soon? Or is the code safe for either Xcode 10.2 beta?

[tkrajacic (Thomas Krajacic)]

Most likely that's just a reference to Xcode that hasn't been updated in the doumentation. Usually you can always use the latest beta of Xcode as far as I know.