Check that GDExtension is opened by compatible Godot version

[dsnopek]

This builds on PR #1193 and adds something that we discussed on issue #1195:

That is, godot-cpp will compare the version of Godot it was built for (based on the extension_api.json that was used) with the version of Godot that is loading it, and ensure that they are compatible, ie. the version of Godot is equal to or greater than the version godot-cpp was built for.

In order to do this, it also:

• Updates the extension_api.json in the repo for Godot 4.2-dev3, since we still had the one from 4.1.1 in there.
• Fixes up the way that we're printing early error messages that happen before godot-cpp is fully initialized. In my testing, I was getting crashes, which I think were caused by the older method using String, because we made some small incompatible changes to String in 4.2. This highlights the need to abort early if an older Godot tries to load a newer GDExtension!

[paddy-exe]

Discussed in GDExtension meeting. Looks good to be except for the point below.
I assume you want to wait for the 4.2 release to merge this? Otherwise the changes to project.godot and the added extension_api.json should be removed

[dsnopek]

Thanks!

I assume you want to wait for the 4.2 release to merge this? Otherwise the changes to project.godot and the added extension_api.json should be removed

No, we've already merged plenty of Godot 4.2 specific changes into godot-cpp's master branch, so I think those changes should be fine. However, I guess they mean I can't do a straight cherry-pick over to the 4.1 branch. :-/ But I could either make a 4.1-specific PR or just not cherry-pick this one.

[paddy-exe]

No, we've already merged plenty of Godot 4.2 specific changes into godot-cpp's master branch, so I think those changes should be fine. However, I guess they mean I can't do a straight cherry-pick over to the 4.1 branch. :-/ But I could either make a 4.1-specific PR or just not cherry-pick this one.

You are absolutely right. Well in that case I will leave the decision up to you👍🏻