Added PHPUnit 12 support and fixed tests, fixed PHP8.4 related deprecation notices, formatted to match PSR-12

[elcreator]

@acharron-hl I saw PHP8.4 upgrade in the garden-container so upgraded it's version in this repo too.

[CLAassistant]

All committers have signed the CLA.

[elcreator]

All tests passed without failing, Psalm and Code Sniffer were also successfully executed.

[Donatello-za]

Unfortunately my old php 8.1 pull request was never accepted as well. I am assuming that the project maintainer is not active on the project and just touches it every 2 years or so.

For anyone that wants to use this PHP 8.4 pull request/fork, you can install it directly from the contributor using this:

composer config repositories.garden-cli vcs https://github.com/elcreator/garden-cli
composer require vanilla/garden-cli:dev-master