chore: Add trunk branch to matrix

[aragon999]

Merge once the build is working again.

[shyim]

I think thats because you install phpstan 1 🤔 , in trunk should be already 2 🤔

[aragon999]

I just investigated the issue, the problem is, that due to the flags --prefer-lowest --prefer-stable when installing the composer dependencies, we install symfony/type-info in version 7.1.0.

But this was only compatible with phpstan 1 but not phpstan 2. The issue has been fixed in Symfony 7.1.8: symfony/symfony@ecb34a7

Maybe as a solution symfony/type-info <7.2 should be added to shopware/conflicts for 6.7: https://github.com/shopware/conflicts/blob/6.7.x/composer.json 🤔