Update unit test matrix to modern PHP/WP versions

- Base matrix: PHP 7.4, 8.1, 8.2, 8.3 (stable versions)
- Experimental: PHP 8.4, 8.5 only
- WordPress: 6.6+ (latest and 6.6 for compatibility)
- Removed: PHP 8.0 (outdated), old WP versions (< 6.6)
- Cleaner, focused test coverage on supported versions

Author: ajaydsouza

.github/workflows/unit-tests.yml

@@ -22,21 +22,25 @@ jobs:
       fail-fast: false
       matrix:
         # Notes regarding supported versions in WP:
-        # The base matrix only contains the PHP versions which are supported on all supported WP versions.
-        php: ['8.0', '8.1', '7.4']
+        # Testing against stable PHP versions with WordPress 6.6+
+        php: ['7.4', '8.1', '8.2', '8.3']
         wp: ['latest']
         experimental: [false]
 
         include:
-          # Complement the builds run via the matrix with high/low WP builds for PHP 7.4 and 8.0.
-          # PHP 8.0 is sort of supported since WP 5.6.
-          # PHP 7.4 is supported since WP 5.3.
+          # Test against older supported WordPress version
+          - php: '8.3'
+            wp: '6.6'
+            experimental: false
+          # Experimental builds for upcoming PHP versions
           - php: '8.5'
             wp: 'latest'
             experimental: true
           - php: '8.4'
             wp: 'latest'
             experimental: true
+            wp: 'latest'
+            experimental: true
 
           - php: '8.3'
             wp: 'latest'
@@ -129,4 +133,4 @@ jobs:
       - name: Run the unit tests - multisite
         env:
           WP_MULTISITE: 1
-        run: ./vendor/bin/phpunit
+        run: ./vendor/bin/phpunit