Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit ^5.7 -> satisfiable by phpunit/phpunit[5.7.0, ..., 5.7.27]. - phpunit/phpunit[5.7.0, ..., 5.7.27] require php ^5.6 || ^7.0 -> your php version (8.3.12) does not satisfy that requirement.

Process completed with exit code 2.

The following actions uses node12 which is deprecated and will be forced to run on node16: actions/checkout@v2. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/