Update GitHub build library versions

Upgrade `actions/checkout` to v4 and `actions/cache` to v4 for improved compatibility and performance. Updated changelog to reflect these changes.

.github/workflows/php.yml

@@ -9,7 +9,7 @@ jobs:
                 php: ['7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
         name: PHP ${{ matrix.php }}
         steps:
-            - uses: actions/checkout@v1
+            - uses: actions/checkout@v4
             - name: Install PHP
               uses: shivammathur/setup-php@v2
               with:
@@ -23,7 +23,7 @@ jobs:
               id: composer-cache
               run: echo "::set-output name=dir::$(composer config cache-files-dir)"
             - name: Cache dependencies
-              uses: actions/cache@v1
+              uses: actions/cache@v4
               with:
                   path: ${{ steps.composer-cache.outputs.dir }}
                   key: ${{ matrix.php }}-composer-${{ hashFiles('**/composer.lock') }}

CHANGELOG.md

@@ -4,6 +4,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## UNRELEASED
+### Added
+- Tests for PHP 8.3 and 8.4
+
+### Changed
+- Upgraded GitHub build library versions: `actions/checkout` and `actions/cache`
+
 ## [v3.3.1] - 2023-01-27
 ### Added
 - Tests for PHP 8.0, 8.1, and 8.2