Add PHP 8.4 support for 1.7.x by dropping support for PHP < 7.1

[MyIgel]

• Re-add optional nullable which got implemented in [PHP 8.4] Fixes for implicit nullability deprecation #871 and reverted in run tests using GitHub actions #873 (due to its PHP < 7.1 incompatibility?)
• Drop support for PHP 5.2, 5.4, 5.5, 5.6, 7.0 because only PHP 7.1 supports optional nullables (and is also unsupported for ages)
• Fix PHPUnit warning of missing name attribute in tests
• Fix CommonMark tests on PHP >= 7.2 by matching the inherited setUp return type

[MyIgel]

This could also be the fix for #897 when released

[Evgeny1973]

@erusev Is there going to be a new release anytime?

[tacman]

Please don't sacrifice PHP 8.4 compatibility for long-dead versions of PHP or any other library. Anyone still using something that old likely isn't updating this library, but is instead inside of code that hasn't be touched in years.

[u01jmg3]

Could this be released as v2? Anyone updating their dependencies would explicitly have to update this dependency to be v2 thus preventing unwanted breakages.

[xPaw]

To prevent confusion: all these changes are already merged in the master branch. This PR is specifically trying to update the 1.7.x branch.

[tacman]

Great. A new release would be welcome.

[BafS]

You can use dev-master to have the latest version compatible with PHP8.4 (not the best practice but there is no other tags)

[LukeWCS]

Hi

I'm currently updating a test suite for phpBB extensions, and I'm using this tool, among other things.

Please don't sacrifice PHP 8.4 compatibility for long-dead versions of PHP or any other library.

I agree.

PHP 5 is no longer relevant today, and PHP 7 is also long outdated. You shouldn't implement "complicated" workarounds for outdated PHP versions, especially when the solution to the implicitly nullable problem is very compact and can be solved natively.

edit:

I should read all the comments before writing one myself. ;-) I missed this:

To prevent confusion: all these changes are already merged in the master branch.

Thx @xPaw