[Swift] removing Swift2 client

[d-date]

Description

Does anybody still using Swift 2? It makes us confused when improving our client.

Swagger-codegen version

Swagger declaration file content or url

Command line used for generation

Steps to reproduce

Related issues/PRs

Suggest a fix/enhancement

make -l swift option deprecated and remove swift template. we should use -l swift3 or -l swift4.

[jaz-ah]

no we obsoleted Swift2 - we should definitely get rid of the -l swift option.

[wing328]

I suggest we still keep it as there may be use cases in which developers need to work on an iOS app still written in Swift 1.x or 2.x and upgrading to the latest swift is not something they can afford due to time constraint.

We do state that the swift generator is no longer maintained and developers are advised to use swift3 or swift4 instead.

[wing328]

Btw, the Java client generator still supports JDK6 (which has reached EOL a while ago). I think it's a nice-to-have feature to support an old version of a particular language.

[d-date]

I believe that almost of all iOS developers are using Swift3.2 or Swift4.0 now because latest Xcode only supported these.

[xavierjurado]

I think we are safe removing Swift 2 support because according to Apple's AppStore guidelines, all new iOS apps and updates must be built with the iOS 11 SDK, which is only available in Xcode 9. And Xcode 9 no longer supports Swift 2.