[FSSDK-9415] Prep for 4.0.0 release (#272)

* Update EventBuilder.php w version 4.0.0

* Update EventBuilderTest.php

* Update CHANGELOG.md

* Update CHANGELOG.md

* Update README.md

Author: Mat001

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Optimizely PHP SDK Changelog
 
+## 4.0.0
+June 12, 2023
+
+* Provided support for PHP version 8.x.
+* Version 4.0.0 requires PHP8+.
+* Version 3 requires PHP5.5+ up to PHP7.
+
 ## 3.9.4
 March 29 , 2023
 

README.md

@@ -19,6 +19,9 @@ Refer to the [PHP SDK's developer documentation](https://docs.developers.optimiz
 
 To access the Feature Management configuration in the Optimizely dashboard, please contact your Optimizely account executive.
 
+SDK version 4.0.0 requires PHP8+.
+SDK version 3 requires PHP5.5+ up to PHP7.
+
 ### Install the SDK
 
 The Optimizely PHP SDK can be installed through [Composer](https://getcomposer.org/). Please use the following command:

src/Optimizely/Event/Builder/EventBuilder.php

@@ -39,7 +39,7 @@ class EventBuilder
     /**
      * @const string Version of the Optimizely PHP SDK.
      */
-    const SDK_VERSION = '3.9.4';
+    const SDK_VERSION = '4.0.0';
 
     /**
      * @var string URL to send event to.

tests/EventTests/EventBuilderTest.php

@@ -69,7 +69,7 @@ protected function setUp() : void
                 ]],
                 'revision' => '15',
                 'client_name' => 'php-sdk',
-                'client_version' => '3.9.4',
+                'client_version' => '4.0.0',
                 'anonymize_ip'=> false,
                 'enrich_decisions' => true,
             ];