chore(deps): fix deprecations of PHPUnit and friends on PHP8.4

[ChristophWurst]

Fixes

• PHP Deprecated: PhpParser\Parser::parse(): Implicitly marking parameter $errorHandler as nullable is deprecated, the explicit nullable type must be used instea
• PHP Deprecated: PharIo\Manifest\Manifest::isExtensionFor(): Implicitly marking parameter $version as nullable is deprecated, the explicit nullable type must be used instead
• PHP Deprecated: SebastianBergmann\GlobalState\Snapshot::__construct(): Implicitly marking parameter $excludeList as nullable is deprecated, the explicit nullable type must be used instea