Release a new version to cocoapods

Summary: Xcode 10.2 drops the support of swift version 3.0. Thus updated the swift version and also the yoga dependency.

Reviewed By: SidharthGuglani

Differential Revision: D14684332

fbshipit-source-id: d42e5979639c9fceec81627d4ac153566c2c0ab1

.swift-version

@@ -1 +1 @@
-3.0
+4.0

YogaKit.podspec

@@ -6,10 +6,10 @@
 #
 podspec = Pod::Spec.new do |spec|
   spec.name = 'YogaKit'
-  spec.version = '1.12.0'
+  spec.version = '1.12.0-pre.1'
   spec.license =  { :type => 'MIT', :file => "LICENSE" }
   spec.homepage = 'https://facebook.github.io/yoga/'
-  spec.documentation_url = 'https://facebook.github.io/yoga/docs/api/yogakit/'
+  spec.documentation_url = 'https://facebook.github.io/yoga/docs/'
 
   spec.summary = 'Yoga is a cross-platform layout engine which implements Flexbox.'
   spec.description = 'Yoga is a cross-platform layout engine enabling maximum collaboration within your team by implementing an API many designers are familiar with, and opening it up to developers across different platforms.'
@@ -23,12 +23,11 @@ podspec = Pod::Spec.new do |spec|
   spec.platform = :ios
   spec.ios.deployment_target = '8.0'
   spec.ios.frameworks = 'UIKit'
-
-  spec.dependency 'Yoga', '~> 1.9'
+  spec.dependency 'Yoga', '1.12.0-pre.1'
   spec.source_files = 'YogaKit/Source/*.{h,m,swift}'
   spec.public_header_files = 'YogaKit/Source/{YGLayout,UIView+Yoga}.h'
   spec.private_header_files = 'YogaKit/Source/YGLayout+Private.h'
-  spec.swift_version = '3.0'
+  spec.swift_version = '4.0'
 end
 
 # See https://github.com/facebook/yoga/pull/366