CI: Add PHP 8.4 to the matrix

Author: alecpl

.github/workflows/ci.yml

@@ -74,7 +74,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: ["7.3", "7.4", "8.0", "8.1", "8.2", "8.3"]
+        php: ["7.3", "7.4", "8.0", "8.1", "8.2", "8.3", "8.4"]
 
     name: Test / PHP ${{ matrix.php }}