Run tests on PHP 8.3 and update test suite

[yadaiio]

This pull request builds on top of #108 #107 and #105.

References: clue/reactphp-csv#33, reactphp/socket#300 and reactphp/socket#299.

After this pull request is merged, we can continue with #112

[SimonFrings]

Thanks for filing this pull request 👍

I added a few remarks below, should both be quick fixes.

I also noticed that the test suite currently reports unhandled promise rejections in this project (see reactphp/promise#248 and https://github.com/orgs/reactphp/discussions/525 for reference), but I think this is something for a follow-up PR. I will look into this.

[yadaiio]

Tysm @SimonFrings for seeing both mistakes! Helps me a lot for the future. 🥳 Should be alright now!

[SimonFrings]

Thanks for applying the changes, looking good 👍

[clue]

@yadaiio Thanks for filing this PR!

I've updated the PR to no longer report any deprecations as reported in #114. This PR now no longer reports any test errors and focuses on adding PHP 8.3 only.

I'll file separate follow-up PRs to address the deprecations reported in #114 and the unhandled promise rejections reported in #115.

[yadaiio]

Thank you @clue for the update 👍