Fix implicit nullable type to avoid PHP 8.4 warnings

[eiriksm]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	fixes #X, partially #Y, mentioned in #Z
Documentation	if this is a new feature, link to pull request in https://github.com/php-http/documentation that adds relevant documentation
License	MIT

What's in this PR?

This PR makes the implicit nullable type explicit. Using implicit nullable types has been deprecated, and will emit deprecation warnings in PHP 8.4

Why?

To avoid getting deprecation warnings in PHP 8.4

Checklist

• Updated CHANGELOG.md to describe BC breaks / deprecations | new feature | bugfix
• Documentation pull request created (if not simply a bugfix)

[GrahamCampbell]

Can we add PHP 8.4 to the CI, too?

[eiriksm]

Can we add PHP 8.4 to the CI, too?

done 🤓

[GrahamCampbell]

Fixes similar to php-http/httplug#176 are needed.

[eiriksm]

added the "emulate php 8.3" part, but not sure which tweak is needed to fix phpcs. Which by the way should probably be a separate PR, as it does not relate to the changes in this PR

[GrahamCampbell]

The tweak is needed to get it to pass, because the symfony ruleset has changed and the php-cs-fixer version is not pinned.

[dbu]

i updated the cs fixer and apply the fixes in #248. that includes the ? for nullable parameters.

can you please rebase on the 2.x branch? that should make the cs fixer green.

[eiriksm]

✅

[dbu]

thanks a lot!

[eiriksm]

amazing. thank you so much for being so responsive 😄

Any chance we could also cut a new release with this change? 🤓

[dbu]

thanks for contributing. i tagged the release: https://github.com/php-http/client-common/releases/tag/2.7.2