[csharp] Fix port of 2154

spine-csharp/src/Attachments/RegionAttachment.cs

@@ -97,7 +97,7 @@ namespace Spine {
 			if (region == null) {
 				uvs[BLX] = 0;
 				uvs[BLY] = 0;
-				uvs[ULX] = 1;
+				uvs[ULX] = 0;
 				uvs[ULY] = 1;
 				uvs[URX] = 1;
 				uvs[URY] = 1;