Add PHP 8.3 support

[MauricioFauth]

Q	A
New Feature	yes

Description

Adds support for PHP 8.3.

[boesing]

Thanks for providing the initial patch.

Please note that we do not yet have PHP 8.3 within our CI pipeline and thus we are not testing anything here.
I'll add a label so that we do not accidentally merge this.

Once we have PHP 8.3 available within the CI pipeline, we will re-trigger the workflow(s).

[boesing]

Nice, CI passing.

PHP version: PHP 8.3.0RC1 (cli) (built: Sep  2 2023 06:34:23) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.3.0RC1, Copyright (c) Zend Technologies
    with Zend OPcache v8.3.0RC1, Copyright (c), by Zend Technologies

Thanks, @MauricioFauth!