chore: Prepare 1.0.0-beta4 release. (#153)

Author: Michael Ng

CHANGELOG.MD

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## [Unreleased]
 Changes that have landed but are not yet released.	Changes that have landed but are not yet released.
 
+## [1.0.0-beta4] - October 28th, 2019
+
+### New Features
+- feat(logger): Expand LogConsumer interface to have explicit field mapping. [#147](https://github.com/optimizely/go-sdk/pull/147)
+
+### Bug Fixes
+- refac(client): Revise how the client handles and returns errors. [#151](https://github.com/optimizely/go-sdk/pull/151)
+
 ## [1.0.0-beta3] - October 15th, 2019
 
 ### Breaking Changes

README.md

@@ -251,3 +251,7 @@ License (MIT): https://github.com/stretchr/testify/blob/master/LICENSE
 json-iterator
 Copyright (c) 2016 json-iterator
 License (MIT): https://github.com/json-iterator/go/blob/master/LICENSE
+
+subset
+Copyright (c) 2015, Facebook, Inc. All rights reserved.
+License (BSD): https://github.com/facebookarchive/subset/blob/master/license

pkg/version.go

@@ -18,7 +18,7 @@
 package pkg
 
 // Version is the current version of the client
-const Version = "1.0.0-beta3"
+const Version = "1.0.0-beta4"
 
 // ClientName is the name of the client
 const ClientName = "go-sdk"