PHP 8.4 Explicit Nullable Parameter Support

[krunchyklown]

PHP 8.4 has been out for a while now (current version is 8.4.5 at the time of writing this issue).

One of the breaking changes in 8.4, is the use of explicit nullable types, as shown here: explicit nullable types explained in PHP 8.4

The good news is this is an easy fix, with a change from this:

function test(string $test = null) {}

to this:

function test(?string $test = null) {}

I'll take a look and see if I can propose a patch for the protobuf package to make this change, but anyone trying to use this package in PHP 8.4 will run into this issue

[krunchyklown]

#26