Expand PHPUnit testing matrix to include versions 12 and 13
Added PHPUnit versions 12 and 13 to the testing matrix and updated exclusions for PHP versions 7.4, 8.0, and 8.1 accordingly.
Added PHPUnit versions 12 and 13 to the testing matrix and updated exclusions for PHP versions 7.4, 8.0, and 8.1 accordingly.