Fix implicit nullable types; Add PHP 8.4 support

[Lakshan-Madushanka]

Implicitly marking parameter as nullable is deprecated in PHP 8.4.

I used this package in my project but when upgrading to PHP 8.4 getting deprecated notices Implicitly marking parameter $length as nullable is deprecated ...

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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[jnoorman]

You can also use the '?' in front of the type in php8.4. For example int $xx = null; could become ?int $xx = null; rather than remove the type for the function declaration.