🚀 Update podspec to version 1.1.0-beta4 [skip ci]

BitcoinKit.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |spec|
   spec.name = 'BitcoinKit'
-  spec.version = '1.0.2'
+  spec.version = '1.1.0-beta4'
   spec.summary = 'Bitcoin(BCH/BTC) protocol toolkit for Swift'
   spec.description = <<-DESC
                        The BitcoinKit library is a Swift implementation of the Bitcoin(BCH/BTC) protocol. This library was originally made by Katsumi Kishikawa, and now is maintained by Yenom Inc. It allows maintaining a wallet and sending/receiving transactions without needing a full blockchain node. It comes with a simple wallet app showing how to use it.
@@ -17,7 +17,7 @@ Pod::Spec.new do |spec|
   spec.exclude_files = 'Sources/**/LinuxSupport.swift'
   spec.module_map = 'BitcoinKit/BitcoinKit.modulemap'
   spec.ios.deployment_target = '8.0'
-  spec.swift_version = '4.1'
+  spec.swift_version = '4.2'
 
   spec.pod_target_xcconfig = { 'SWIFT_WHOLE_MODULE_OPTIMIZATION' => 'YES',
                                'APPLICATION_EXTENSION_API_ONLY' => 'YES',