Add URP render pass API parity shims

managed/XCEngine.ScriptCore/Rendering/Core/CommandBuffer.cs

@@ -0,0 +1,18 @@
+namespace XCEngine.Rendering
+{
+    public sealed class CommandBuffer
+    {
+        public CommandBuffer()
+            : this(string.Empty)
+        {
+        }
+
+        public CommandBuffer(
+            string name)
+        {
+            this.name = name ?? string.Empty;
+        }
+
+        public string name { get; set; }
+    }
+}