fix: php 8.4 deprecation warning about nullable parameters

[marksgerasimovs]

With php 8.4 deprecation warnings appear
marking parameter %s as nullable is deprecated, the explicit nullable type must be used instead
To set nullable type had to bump min. required php version to 7.1 though

List of common tasks a pull request require complete

• Changelog entry is added or the pull request don't alter library's functionality

[ChagarinIvan]

Also waiting for these changes.

[DeepDiver1975]

This change would require a major release ...

[DeepDiver1975]

please adjust the GitHub workflow configuration - thx

[marksgerasimovs]

please adjust the GitHub workflow configuration - thx

updated readme.md also

[marksgerasimovs]

@DeepDiver1975 Sorry, I don't want to be annoying, but pinging again, maybe notification was lost, hope you see this, please check if all good. We need this.

[marksgerasimovs]

@jumbojett greetings, is there any extra requirements ? I wonder on possibility this can get released ?

[q2apro]

Please release the fixes.

[DeepDiver1975]

changelog is missing ..... will add on release....

[W0rma]

This change would require a major release ...

@DeepDiver1975 Why do you think that a major release is necessary? Is it because this PR dropped support for PHP 7.0?

I'm just asking because mixing implicitly nullable parameters with explicitly nullable parameters does not seem to cause any BC breaks (see https://3v4l.org/VmY1C).

It would be great to have a new patch release for this package.

[miloshynek]

When do you plan to release a new release version?

[Buzka91]

@DeepDiver1975 great PHP 8.4 fixes are merged, please release new tag

[ydelwiche]

This change would require a major release ...

Why major? The changes have no impact on current implementations. It can be a patch (according to SemVer principles).

[marksgerasimovs]

This change would require a major release ...

Why major? The changes have no impact on current implementations. It can be a patch (according to SemVer principles).

Because php version support changed, this will not run on php 7.0, so in terms of semver for php 7.0 project this is breaking change.