The `.gitlab-ci.yml` file was updated to remove the `phpstan` job. This change means we will no
longer run static analysis automatically on our CI pipeline. Further discussions may be needed on
whether to replace this with another tool or integrate it differently.

Debug test

In this commit, modifications have been made to the .gitlab-ci.yml file to allow running PHPUnit on
PHP 8.3 in our pipeline. A new job `modify-job` was added which runs phpstan script with following
instructions:

- Keeping other autoloaders with `QUIQQER_OTHER_AUTOLOADERS=KEEP`
- Disabling progress display with `--no-progress`
- Removing memory limit with `--memory-limit=-1`
- Enabling debug mode with `--debug`