[unity] BoneFollower should use cached value.

spine-unity/Assets/spine-unity/BoneFollower.cs

@@ -165,10 +165,10 @@ namespace Spine.Unity {
 					Vector3 worldRotation = skeletonTransform.rotation.eulerAngles;
 					if (followLocalScale && bone.scaleX < 0) boneWorldRotation += 180f;
 					#if UNITY_5_6_OR_NEWER
-					thisTransform.SetPositionAndRotation(targetWorldPosition, Quaternion.Euler(worldRotation.x, worldRotation.y, skeletonTransform.rotation.eulerAngles.z + boneWorldRotation));
+					thisTransform.SetPositionAndRotation(targetWorldPosition, Quaternion.Euler(worldRotation.x, worldRotation.y, worldRotation.z + boneWorldRotation));
 					#else
 					thisTransform.position = targetWorldPosition;
-					thisTransform.rotation = Quaternion.Euler(worldRotation.x, worldRotation.y, skeletonTransform.rotation.eulerAngles.z + bone.WorldRotationX);
+					thisTransform.rotation = Quaternion.Euler(worldRotation.x, worldRotation.y, worldRotation.z + bone.WorldRotationX);
 					#endif
 				} else {
 					thisTransform.position = targetWorldPosition;