Build failing on MacOS

[nlaha]

https://github.com/nlaha/godot-midi/actions/runs/6605660155/job/17941064231

extension/src/midi_player.cpp:69:54: error: use of overloaded operator '=' is ambiguous (with operand types 'godot::Variant' and 'size_t' (aka 'unsigned long'))
                        this->track_index_offsets[i] = j;
                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~
godot-cpp/include/godot_cpp/variant/variant.hpp:252:11: note: candidate function
        Variant &operator=(const Variant &other);
                 ^
godot-cpp/include/godot_cpp/variant/variant.hpp:253:11: note: candidate function
        Variant &operator=(Variant &&other);
                 ^
In file included from extension/src/midi_player.cpp:1:
In file included from extension/src/midi_player.h:4:
In file included from godot-cpp/include/godot_cpp/core/class_db.hpp:38:
In file included from godot-cpp/include/godot_cpp/core/method_bind.hpp:34:
In file included from godot-cpp/include/godot_cpp/core/binder_common.hpp:36:
In file included from godot-cpp/include/godot_cpp/core/method_ptrcall.hpp:36:
In file included from godot-cpp/include/godot_cpp/core/object.hpp:40:
godot-cpp/gen/include/godot_cpp/classes/object.hpp:89:76: error: ambiguous conversion for functional-style cast from 'const unsigned long' to 'godot::Variant'
                std::array<Variant, 1 + sizeof...(Args)> variant_args { Variant(signal), Variant(args)... };
                                                                                         ^~~~~~~~~~~~

[delaneyparker]

Here is a PR that builds on MacOS, However I'm not sure the size_t to uint64_t conversions are the right thing to do (still getting acquainted w/ the code). Hope this helps!

https://github.com/nlaha/godot-midi/pull/14