fix for making the setter private

fix for making the setter private

Octokit/Models/Response/RepositoryContent.cs

@@ -31,7 +31,7 @@ public RepositoryContent(string name, string path, string sha, int size, Content
         /// The Base64 encoded content if this is a file. Otherwise it's null.
         /// </summary>
         [Parameter(Key = "content")]
-        public string EncodedContent { get; set; }
+        public string EncodedContent { get; private set; }
 
         /// <summary>
         /// The unencoded content. Only access this if the content is expected to be text and not binary content.