Update Projects section (#405)

Move Arrow from 3->4.
GATT is now a plugin instead of a standalone project but still in Godot 3 as far as I can tell,
so moved it to the relevant section.

README.md

@@ -118,6 +118,7 @@ See [Vivraan/godot-lang-support](https://github.com/Vivraan/godot-lang-support).
 
 #### Godot 4
 
+- [Arrow](https://github.com/mhgolkar/Arrow) - A tool to design game narratives with nodes.
 - [Clipboard Narrator](https://github.com/lesleyrs/clipboard-narrator) - Turn any web page into an audiobook, works in the background on desktop!
 - [GodSVG](https://github.com/MewPurPur/GodSVG) - Tool to create optimized Scalable Vector Graphics files.
 - [Lorien](https://github.com/mbrlabs/Lorien) - Infinite-canvas drawing/whiteboarding app for Windows, Linux and macOS. Supports drawing tablets and pressure sensitivity.
@@ -127,8 +128,6 @@ See [Vivraan/godot-lang-support](https://github.com/Vivraan/godot-lang-support).
 
 #### Godot 3
 
-- [Arrow](https://github.com/mhgolkar/Arrow) - A tool to design game narratives with nodes.
-- [GATT - Godot Autotile Texture Templater](https://github.com/sesopenko/gatt) - A tool for generating 2x2 and 3x3 autotile tilesets in whichever size and colour needed.
 - [Godello](https://github.com/alfredbaudisch/Godello) - A Trello-like kanban board application made with Godot. A proof of concept for complex non-game applications with Godot, as well real-time online interactions between multiple users. Includes backend code.
 - [SimulaVR](https://github.com/SimulaVR/Simula) - A VR window manager for Linux, built on top of Godot engine.
 - [vpuppr](https://github.com/virtual-puppet-project/vpuppr) - A cross-platform VTuber application with mulitple tracking backends.
@@ -276,6 +275,7 @@ See [Vivraan/godot-lang-support](https://github.com/Vivraan/godot-lang-support).
 - [Escoria](https://github.com/godotengine/escoria) - Point & click adventure game framework. *(Godot 2 and 3)*
 - [FMOD GDNative](https://github.com/utopia-rise/fmod-gdnative) - Plugin to use the FMOD audio engine in GDScript.
 - [Funexpected Flash Tools](https://github.com/funexpected/flash-tools) - Adobe Animate (Flash) plugin that allows you to export a project for a Godot Engine.
+- [GATT - Godot Autotile Texture Templater](https://github.com/sesopenko/gatt) - A tool for generating 2x2 and 3x3 autotile tilesets in whichever size and colour needed.
 - [GDGIFExporter](https://github.com/jegor377/godot-gdgifexporter) - GIF exporter made entirely in GDScript.
 - [gdstats](https://github.com/droxpopuli/gdstats) - A library of pseudorandom number generators for common statistical distributions.
 - [GdUnit3](https://github.com/MikeSchulze/gdUnit3) - Godot Unit Testing Framework.