Update dependencies

[craigpaul]

This guide was written a couple of years ago at this point and a few of the dependencies (more specifically the PHP dependencies) are quite out of date now. When possible, we should update these dependencies and go back through the guide and various solution branches to make sure it's still a solid set of lessons.

[craigpaul]

We might want to even consider updating the tests, in the case of PHP, to have both PEST and PHPUnit variants 🤔.