Cocoapods: Add doc about swift_version podfile config

[puttin]

How about add sample for the latest released version in guides.cocoapods.org about the attr_accessor :swift_version

something like

target 'MyApp' do
  swift_version = '2.3'
end

people are still using post_install something like this

• [x] I've read and understood the *CONTRIBUTING guidelines and have done my best effort to follow.

5540 #5521

[puttin]

and also the .swift_version for the Pods

5841

[orta]

How about add sample for the latest released version in guides.cocoapods.org about the attr_accessor :swift_version

This isn't on the Podfile ( the full DSL is here: https://github.com/CocoaPods/Core/blob/master/lib/cocoapods-core/podfile/dsl.rb ) - this is generated by looking at your targets and deriving it - it's not a public property because it already exists in Xcode. The post_installs won't be needed in 1.1.0, only the old betas.

and also the .swift_version for the Pods

This was added today, we'll be documenting it - don't worry.

[pcantrell]

Good _lord_ this was difficult to find!

[orta]

I updated the CHANGELOG - which should make it more obvious