Optional ability to install composer packages before running psalm

[Blacksmoke16]

We're currently leveraging https://github.com/psalm/psalm-plugin-symfony along with this action. However, since composer packages are not being installed, the container is never being created resulting in Uncaught Psalm\Exception\ConfigException: Container xml file(s) not found!.

Thoughts on adding the optional ability to also run composer install or some arbitrary command to handle this use case?

[weirdan]

The action does run composer install, however it does it with --no-scripts flag.