Php 8.4 deprecations fix

[acelaya]

This PR solves a deprecation warning reported when using this library in PHP 8.4

The reason for this warning is a protected method from the Factory class which has two arguments implicitly marked as nullable by having a null default value.

ip-lib/src/Factory.php

Line 225 in 125ab84

protected static function rangeFromBoundaryAddresses(AddressInterface $from = null, AddressInterface $to = null)

That is deprecated in PHP 8.4, and will error in PHP 9.0 and above.

One possible approach to solve that is explicitly marking the arguments as nullable (eg. ?AddressInterface $from = null instead of AddressInterface $from = null), but that requires PHP 7.1, and this library supports older versions.

Since the method where this error is reported was protected and being called only from one place, I moved the logic there instead, removing the method entirely.

This can be a breaking change though, if anyone was extending from Factory and invoking this method from their own class, so perhaps this requires a major version bump.

Additionally, this PR also adds PHP 8.3 and 8.4 to the tests workflow matrix.

Closes #89

[coveralls]

coverage: 98.621% (-0.001%) from 98.622%
when pulling beff3a9 on acelaya-forks:php-8.4-deprecations
into 125ab84 on mlocati:main.

[acelaya]

coverage: 98.621% (-0.001%) from 98.622% when pulling beff3a9 on acelaya-forks:php-8.4-deprecations into 125ab84 on mlocati:main.

This is probably a false negative, caused simply by the fact that there's now less total lines.

[mlocati]

#91 is a less intrusive alternative, IMHO

[acelaya]

Oh! That didn't occur to me, and it's backwards compatible.

I'll close mine.

Thanks!