Preparing for 2.4.0 release (#277)

Signed-off-by: Kim Pepper <kim@pepper.id.au>

Author: kimpepper

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
-## [Unreleased]
+## [2.4.0]
 ### Added
 - Generate endpoints from OpenSearch API Specification ([#194](https://github.com/opensearch-project/opensearch-php/pull/194))
 - Added workflow for automated API update using OpenSearch API specification ([#209](https://github.com/opensearch-project/opensearch-php/pull/209))
@@ -44,8 +44,6 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Updated opensearch-php APIs to reflect [opensearch-api-specification@07e329e](https://github.com/opensearch-project/opensearch-api-specification/commit/07e329e8d01fd0576de6a0a3c35412fd5a9163db)
 - Updated opensearch-php APIs to reflect [opensearch-api-specification@1db1840](https://github.com/opensearch-project/opensearch-api-specification/commit/1db184063a463c5180a2cc824b1efc1aeebfd5eb)
 - Updated opensearch-php APIs to reflect [opensearch-api-specification@cb320b5](https://github.com/opensearch-project/opensearch-api-specification/commit/cb320b5482551c4f28afa26ff0d1653332699722)
-### Security
-### Dependencies
 
 ## [2.3.0]
 
@@ -75,7 +73,8 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Fixed basic authentication being overridden by connection params in `ClientBuilder` ([#160](https://github.com/opensearch-project/opensearch-php/pull/160))
 - Fixed PHP warning in `Connection::tryDeserializeError()` for some error responses ([#167](https://github.com/opensearch-project/opensearch-php/issues/167))
 
-[Unreleased]: https://github.com/opensearch-project/opensearch-php/compare/2.3.0...main
+[Unreleased]: https://github.com/opensearch-project/opensearch-php/compare/2.4.0...main
+[2.4.0]: https://github.com/opensearch-project/opensearch-php/compare/2.3.0...2.4.0
 [2.3.0]: https://github.com/opensearch-project/opensearch-php/compare/2.2.0...2.3.0
 [2.2.0]: https://github.com/opensearch-project/opensearch-php/compare/2.1.0...2.2.0
 [2.1.0]: https://github.com/opensearch-project/opensearch-php/compare/2.0.3...2.1.0

src/OpenSearch/Client.php

@@ -65,7 +65,7 @@
  */
 class Client
 {
-    public const VERSION = '2.3.1';
+    public const VERSION = '2.4.0';
 
     /**
      * @var Transport

util/template/client-class

@@ -34,7 +34,7 @@ use OpenSearch\Namespaces\NamespaceBuilderInterface;
 class Client
 {
 
-    const VERSION = '2.3.1';
+    const VERSION = '2.4.0';
 
     /**
      * @var Transport