update c# interop to use percentage

csharp/Facebook.Yoga/Border.cs

@@ -0,0 +1,31 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+namespace Facebook.Yoga
+{
+    public class Border
+    {
+        public float? Top;
+        public float? Bottom;
+        public float? Left;
+        public float? Right;
+
+        public Border(
+            float? top = null,
+            float? bottom = null,
+            float? left = null,
+            float? right = null)
+        {
+            Top = top;
+            Bottom = bottom;
+            Left = left;
+            Right = right;
+        }
+    }
+}