Add Simplified Flight Simulation Library (#298)

Added "Simplified Flight Simulation library" (https://github.com/fbcosentino/godot-simplified-flightsim) to the plugins list.

README.md

@@ -216,6 +216,7 @@ See [Vivraan/godot-lang-support](https://github.com/Vivraan/godot-lang-support).
 - [Scene Manager](https://github.com/glass-brick/Scene-Manager) - Make nice and customizable scene transitions in one line of code (Godot 3.x, 4.0.alpha).
 - [Scrolling Background](https://github.com/dploeger/godot-scrollingbackground) - A scrolling background node (Godot 2.1,3.x).
 - [SimpleGodotCRTShader](https://github.com/henriquelalves/SimpleGodotCRTShader) - A simple Godot shader that simulates CRT Displays (Godot 2.x, 3.x).
+- [Simplified Flight Simulation library](https://github.com/fbcosentino/godot-simplified-flightsim) - A library that helps you create a simple airplane/helicopter/spaceship flight simulator (Godot 3.x, 4.x).
 - [SignalVisualizer](https://github.com/Ericdowney/SignalVisualizer) - Displays the current scene's signals and connections in a easy to read graph and tree dock (Godot 4.x).
 - [SMRT-Godot](https://github.com/brunosxs/SMRT-Godot) - A dialog system and editor fairly customizable, a nice fit for story-driven games (Godot 3.x).
 - [StoryTeller Engine](https://github.com/HeavenMercy/StoryTeller-Engine) - Dialog and interactive fiction engine (Godot 3.x).