Update to Godot 4.0-beta4

[emmyleaf]

Updates godot-cpp to commit 727673a as per godotengine/godot-cpp#874.
Also contains necessary changes to the scons build and one renamed function.
Tested on windows and linux!

[codecat]

Thanks, this looks good! Is the build target change to template_release intentional? Is that not just for template builds, or was there some change?

[emmyleaf]

Yeah, it looks like the targets have been renamed like that for these godot projects:
godotengine/godot-cpp#867
godotengine/godot#66242

[codecat]

Interesting, thanks!