add umbrella entry to breaking changes in changelog for Swift 3 API Guidelines
add umbrella entry to breaking changes in changelog for Swift 3 API Guidelines

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