base64urlsave use utf8 replace ascii

Author: shijiayun

QBox/Util/Base64UrlSafe.cs

@@ -8,7 +8,7 @@ public static class Base64UrlSafe
         public static string Encode(string text)
         {
             if (String.IsNullOrEmpty(text)) return "";
-            byte[] bs = Encoding.ASCII.GetBytes(text);
+            byte[] bs = Encoding.UTF8.GetBytes(text);
             string encodedStr = Convert.ToBase64String(bs);
             encodedStr = encodedStr.Replace('+', '-').Replace('/', '_');
             return encodedStr;