Your requirements could not be resolved to an installable set of packages.
Problem 1
- Root composer.json requires phpunit/phpunit ^11.2.7 -> satisfiable by phpunit/phpunit[11.2.7, 11.2.x-dev, 11.3.x-dev].
- phpunit/phpunit[11.2.7, ..., 11.3.x-dev] require php >=8.2 -> your php version (8.1.29) does not satisfy that requirement.
Problem 2
- orchestra/testbench[v7.0.0, ..., 7.x-dev] require phpunit/phpunit ^9.5.10 -> found phpunit/phpunit[9.5.10, ..., 9.6.x-dev] but it conflicts with your root composer.json require (^11.2.7).
- Root composer.json requires orchestra/testbench 7.* -> satisfiable by orchestra/testbench[v7.0.0, ..., 7.x-dev].