[Symfony] Support Symfony `8.0`

[yt-topicus]

Description

Symfony released 8.0: https://github.com/symfony/symfony/releases/tag/v8.0.0

Example
Currently api-platform/symfony does not support 8.0 yet:

  Problem 2
    - Root composer.json requires api-platform/symfony ^4.1 -> satisfiable by api-platform/symfony[v4.1.0, ..., v4.2.6].
    - api-platform/symfony[v4.1.0, ..., v4.1.27] require symfony/property-info ^6.4 || ^7.1 -> found symfony/property-info[v6.4.0, ..., v6.4.24, v7.1.0, ..., v7.3.5] but it conflicts with your root composer.json require (8.0.*).
    - api-platform/symfony[v4.2.0, ..., v4.2.2] require symfony/finder ^6.4 || ^7.0 -> found symfony/finder[v6.4.0, ..., v6.4.27, v7.0.0, ..., v7.3.5] but these were not loaded, likely because it conflicts with another require.
    - api-platform/symfony[v4.2.3, ..., v4.2.6] require symfony/asset ^6.4 || ^7.0 -> found symfony/asset[v6.4.0, ..., v6.4.24, v7.0.0, ..., v7.3.0] but it conflicts with your root composer.json require (8.0.*).

[rvanlaak]

As symfony/6.4 is supported until end of November 2027, and as new APIP majors are expected to be released every two years, when will be the time to start working on the 5.x branch?

In what way does APIP follow supported PHP versions? Symfony 6.4 is pinned to PHP 8.1, and security support for that version ends in a month: https://www.php.net/supported-versions.php

Does the current main default branch target the 5.0 or another 4.x release?

[soyuka]

Not sure to understand @rvanlaak ?