Add publishing for Conan artifact

Hi,

This library works great for creating high performance code for Godot, but it is rather difficult to install compared to other bindings. For most bindings (Rust, nim, D), there is some sort of package manager which allows the bindings to be installed with one line of configuration.

Considering Conan seems to be the leading Open Source package manager for C++, it would be nice if this was published to Conan so beginners (like myself) could get started much faster, especially because the C++ bindings are officially supported.