allow forcing Swift version via SWIFTLINT_SWIFT_VERSION
allow forcing Swift version via SWIFTLINT_SWIFT_VERSION

victorpimentel/SwiftLint,lyft/SwiftLint,Johnykutty/SwiftLint,jeffreybergier/SwiftLint,Johnykutty/SwiftLint,firebase/SwiftLint,realm/SwiftLint,firebase/SwiftLint,realm/SwiftLint,firebase/SwiftLint,jeffreybergier/SwiftLint,jeffreybergier/SwiftLint,lyft/SwiftLint,realm/SwiftLint,Johnykutty/SwiftLint,realm/SwiftLint,jeffreybergier/SwiftLint,victorpimentel/SwiftLint,firebase/SwiftLint,Johnykutty/SwiftLint,victorpimentel/SwiftLint,lyft/SwiftLint,lyft/SwiftLint,victorpimentel/SwiftLint