CB-14224 Default.rd.xml header fixes (#284)

* add license text
* add GitHub link
diff --git a/template/Properties/Default.rd.xml b/template/Properties/Default.rd.xml
index 7c40ffe..3b46199 100644
--- a/template/Properties/Default.rd.xml
+++ b/template/Properties/Default.rd.xml
@@ -13,6 +13,31 @@
 
     Using the Namespace directive to apply reflection policy to all the types in a particular namespace
     <Namespace Name="DataClasses.ViewModels" Seralize="All" />
+
+    The MIT License (MIT)
+
+    Copyright (c) Microsoft Corporation
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+    Source:
+    https://github.com/Microsoft/Windows-universal-samples/blob/master/SharedContent/cs/Default.rd.xml
 -->
 
 <Directives xmlns="http://schemas.microsoft.com/netfx/2013/01/metadata">