ci(git-action): auto release prep for 4.0.0 (#547)

Co-authored-by: optibot <optibot@users.noreply.github.com>

Author: optibot

OptimizelySwiftSDK.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
   s.name                    = "OptimizelySwiftSDK"
   s.module_name	            = "Optimizely"
-  s.version                 = "4.0.0-beta"
+  s.version                 = "4.0.0"
   s.summary                 = "Optimizely experiment framework for iOS/tvOS/watchOS"
   s.homepage                = "https://docs.developers.optimizely.com/experimentation/v4.0.0-full-stack/docs"
   s.license                 = { :type => "Apache License, Version 2.0", :file => "LICENSE" }

Sources/Utils/SDKVersion.swift

@@ -17,4 +17,4 @@
 /// Do not edit this field.
 /// - It is auto updated (Scripts/updated_version.sh) to reflect the current version
 /// - Do not put underscores in the name (Swiftlint can modify unexpectedly)
-let OPTIMIZELYSDKVERSION = "4.0.0-beta"
+let OPTIMIZELYSDKVERSION = "4.0.0"