fix(PHPUnit): Increased memory_limit, to be able to run all tests on MacOS

[fbett]

Reason:
128M was not enough to run all unit tests

The expected memory usage seems to be between 180M (MacOS M3) and 350M (Github's Workflow Runner)

Previous #335

[stelgenhof]

@fbett Your code is failing because of new PHP CS rules. Please run the following on your PR/branch:
composer cs-fix. And also run the tests locally first before committing: composer test.

When all is without errors, please commit. Then it should be good! :)

[fbett]

This PR does not contain any code - only a small appendix to the phpunit config file.

If i run composer cs-fix on the develop branch, the script modifies more than 1600 files.
Please run the commands on the develop branch to prevent problems like this.

[stelgenhof]

@fbett Yes correct, I was thinking of your other PR. Anyway, the develop branch is already up to date. You just need to rebase your branch.

[fbett]

No, the develop branch is not up to date. I have already created a new fork.

[stelgenhof]

Apologies, you're correct (sorry long day). I will update the develop branch right away.

[fbett]

Thank you. The commit is rebased.