Adds proper IBuffer usage instead of dynamic flag.

Comments By: phosit
Differential Revision: https://code.wildfiregames.com/D5281
This was SVN commit r28107.

source/renderer/SkyManager.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2023 Wildfire Games.
+/* Copyright (C) 2024 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -40,7 +40,8 @@
 #include <algorithm>
 
 SkyManager::SkyManager()
-	: m_VertexArray(Renderer::Backend::IBuffer::Type::VERTEX, false)
+	: m_VertexArray(Renderer::Backend::IBuffer::Type::VERTEX,
+		Renderer::Backend::IBuffer::Usage::TRANSFER_DST)
 {
 	CFG_GET_VAL("showsky", m_SkyVisible);
 }