majorVersion only in Package.swift dependencies when dependancies have that

[mattcolegate]

Once all our dependencies have moved to majorVersion only in their Package.swifts, our Package.swift must also change to majorVersion only. This will allow SwiftMetrics to work with more versions of our dependencies, which in turn will allow more versions of our dependents to work with SwiftMetrics.
Awaiting the following projects to change:

https://github.com/IBM-Swift/Kitura-Request
https://github.com/IBM-Swift/Kitura-net
https://github.com/IBM-Swift/BlueSSLService