Revert "Upgrade the project to Unity 2021 LTS"

Assets/Rendering/UniversalRenderPipeline2DRenderer.asset

Assets/Rendering/UniversalRenderPipelineAsset.asset

Assets/Scenes/MainMenu.unity

Assets/Scenes/Simulation.unity

Assets/Scripts/Presentation/World/TileHighlight.cs

Assets/UI/AppPanelSettings.asset

Assets/UI/AppPanelSettings.asset.meta

Assets/UniversalRenderPipelineGlobalSettings.asset

Assets/UniversalRenderPipelineGlobalSettings.asset.meta

Packages/manifest.json

Packages/packages-lock.json

ProjectSettings/GraphicsSettings.asset

ProjectSettings/MemorySettings.asset

ProjectSettings/ProjectSettings.asset

ProjectSettings/ProjectVersion.txt

ProjectSettings/RiderScriptEditorPersistedState.asset

ProjectSettings/SceneTemplateSettings.json

ProjectSettings/ShaderGraphSettings.asset

ProjectSettings/URPProjectSettings.asset

ProjectSettings/boot.config