[FSSDK-8963] Version bump (#262)

(cherry picked from commit a32e27e)

Author: mikechu-optimizely

src/Optimizely/Event/Builder/EventBuilder.php

@@ -39,7 +39,7 @@ class EventBuilder
     /**
      * @const string Version of the Optimizely PHP SDK.
      */
-    const SDK_VERSION = '3.9.1';
+    const SDK_VERSION = '3.9.3';
 
     /**
      * @var string URL to send event to.

tests/EventTests/EventBuilderTest.php

@@ -68,7 +68,7 @@ public function setUp()
                 ]],
                 'revision' => '15',
                 'client_name' => 'php-sdk',
-                'client_version' => '3.9.1',
+                'client_version' => '3.9.3',
                 'anonymize_ip'=> false,
                 'enrich_decisions' => true,
             ];