Upload 4.x demos to the asset library

[diguifi]

Which demo project is affected:
godotengine/godot-demo-projects/tree/master/3d/platformer

OS/device including version:
_

Issue description:
The project is tagged as 3.5 at the asset store, when it has been updated to version 4 recently. I think this is an important matter since I and many others have been targeting v4 only on the asset store.

Screenshots of issue:

[Calinou]

• Related to Screenshots are broken on asset library due to file name/format change #895.

The 4.0 demos aren't uploaded to the asset library yet. Note that some demos weren't ported to 4.0 yet, so not all 3.x demos have a working 4.0 counterpart yet.

[Calinou]

As per the tracker, there are still a few demos pending an update so we can upload all 4.x demos at once on the asset library. These can prove to be difficult to update in a fully functional manner, so maybe it's better to upload what works now and upload the rest later once they're ported. I'll look into doing this at some point.

[Calinou]

All 4.2 demos are now on the asset library, with a few exceptions as these demos are currently not functional in the master branch:

• 3D IK Demo
• UI Mirroring Demo
• 2.5D with C# Demo
• Android In-App Purchases with C# Demo
• Dodge the Creeps with C# Demo
• Pong Multiplayer with C# Demo
• WebRTC Minimal Connection Demo
• WebRTC Signaling Demo