explicitly specify a swift version of 3.0
explicitly specify a swift version of 3.0

to support compiling with Xcode 9 beta 3 in Swift 3 mode

lyft/SwiftLint,lyft/SwiftLint,realm/SwiftLint,lyft/SwiftLint,lyft/SwiftLint,realm/SwiftLint,realm/SwiftLint,realm/SwiftLint