chore: prepare for release 3.8.0 (#280)

Author: jaeopt

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Optimizely Ruby SDK Changelog
 
+## 3.8.0
+February 16th, 2021
+
+### New Features:
+- Introducing a new primary interface for retrieving feature flag status, configuration and associated experiment decisions for users ([#274](https://github.com/optimizely/ruby-sdk/pull/274), [#279](https://github.com/optimizely/ruby-sdk/pull/279)). The new `OptimizelyUserContext` class is instantiated with `create_user_context` and exposes the following APIs to get `OptimizelyDecision`:
+
+    - set_attribute
+    - decide
+    - decide_all
+    - decide_for_keys
+    - track_event
+
+- For details, refer to our documentation page: https://docs.developers.optimizely.com/full-stack/v4.0/docs/ruby-sdk.
+
 ## 3.7.0
 November 20th, 2020
 

lib/optimizely/version.rb

@@ -17,5 +17,5 @@
 #
 module Optimizely
   CLIENT_ENGINE = 'ruby-sdk'
-  VERSION = '3.7.0'
+  VERSION = '3.8.0'
 end

spec/project_spec.rb

@@ -3625,7 +3625,7 @@ def callback(_args); end
           project_id: '111001',
           revision: '42',
           client_name: 'ruby-sdk',
-          client_version: '3.7.0',
+          client_version: '3.8.0',
           anonymize_ip: false,
           enrich_decisions: true,
           visitors: [{
@@ -3771,7 +3771,7 @@ def callback(_args); end
           project_id: '111001',
           revision: '42',
           client_name: 'ruby-sdk',
-          client_version: '3.7.0',
+          client_version: '3.8.0',
           anonymize_ip: false,
           enrich_decisions: true,
           visitors: [{